JPS6045783A - Ignition device for condenser discharging type internal- combustion engine - Google Patents

Abstract

PURPOSE:To make the output of a generator coil rectifiable with a full-wave rectifier circuit, by making up such a period of time that an anode current for discharging control thyristor use comes to zero in time of being ignited by a generator coil short-circuiting thyristor. CONSTITUTION:The output of an AC generator coil 5 is rectified by full-wave rectifier circuits (diodes 61 and 62) whereby a condenser 3 is charged with polarity (illustrated herein). When an ignition signal ig is fed to a gate of a discharging control thyristor from a signal feed circuit, simultaneously a trigger current igs is also fed to a gate of a generator coil short-circuiting thyristor 9. Therefore, the thyristor 9 is conducted with current, and since a short-circuit current flows therein through the thyristor 9, an electric current is in no case fed to a thyristor 4 from the side of the generator coil 5. With this constitution, even when the output of the generator coil is rectified with a full-wave rectifier circuit, accurate ignition is thus performable.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a capacitor discharge type ignition device for an internal combustion engine.

BACKGROUND OF THE INVENTION As a conventional ignition device of this type, one shown in FIG. 1 is known. In the figure, 1 is an ignition coil having a primary coil 1a and a secondary coil 1b, and 2 is a spark plug attached to a cylinder of an internal combustion engine (not shown) and connected to the secondary coil 1b of the ignition coil. One ends of the coil 1a and the secondary coil 1b are grounded. An ignition energy storage capacitor 3 is connected to the non-grounded terminal of the primary coil 1a.
A thyristor 4 for discharge control is connected in parallel between the other end of the capacitor and the ground with its cathode facing the ground. Reference numeral 5 denotes a power generating coil disposed within a magnet generator driven by the engine, and its intermediate tap is grounded as a neutral point N. The anodes of diodes 61 and 62 are connected to one end and the other end of the non-grounded side of the generating coil 5, respectively, and the cathodes of both diodes are commonly connected to the connection point between the capacitor 3 and the anode of the thyristor 4. An ignition timing signal ig is supplied to the thyristors 4 from the signal supply circuit 7 .

In this ignition system, an alternating current voltage is induced in the generator coil 5 in synchronization with the rotation of the engine, and this voltage is rectified by a full-wave rectifier circuit consisting of diodes 61 and 62 and applied to the capacitor 3. Capacitor 3 is therefore charged to the polarity shown. When an ignition timing signal is supplied from the signal supply circuit 7 to the thyristor 4 at the ignition timing of the engine, the thyristor 4 becomes conductive and transfers the charge in the capacitor 3 to the ignition coil 1.
Next, a discharge is caused through the coil 1a. This causes a large magnetic flux change in the iron core of the ignition coil, and the secondary coil 1
A high voltage is generated at b. Therefore, a spark is produced in the spark plug and the engine is ignited.

As mentioned above, if the ignition energy storage capacitor is charged by the full-wave rectified output of the generator coil 5, more energy will be stored in the capacitor than if the ignition energy storage capacitor is charged by the half-wave rectified output. ignition performance can be improved. However, in this ignition device, at the same time when the discharge control thyristor 4 becomes conductive, a short-circuit current in one of the coils on both sides of the neutral point N of the generating coil 5, for example, the coil 51, flows through the thyristor 4, and this short-circuit current flows through the thyristor 4. Since the voltage of the other coil 52 is applied to the thyristor 4 at the same time as the current ends, the thyristor 4 often becomes conductive again, which has the drawback that commutation of the thyristor 4 tends to fail.

OBJECTS OF THE INVENTION The object of the present invention is to provide a capacitor-discharge type internal combustion system which charges an ignition energy storage capacitor with the full-wave rectified output of an alternating current generator coil and also ensures commutation of a discharge control thyristor. Our objective is to provide an engine ignition system.

Structure of the Invention The present invention provides a power generation coil disposed in an AC generator driven by an internal combustion engine, a rectifier circuit for full-wave rectification of the output of the power generation coil, an ignition coil, and one of the ignition coils.
an ignition energy storage capacitor disposed on the next side and charged to one polarity by the output of the rectifier circuit; and a cathode disposed so as to discharge the electric charge of the capacitor through the primary coil of the ignition coil when conductive. A capacitor discharge type ignition device for an internal combustion engine, comprising a discharge control thyristor that is grounded, and a signal supply circuit that supplies an ignition timing signal to the gate of the discharge control thyristor at the ignition timing of the internal combustion engine, In the present invention, a thyristor for short-circuiting the generating coil with its cathode facing the ground side is connected in parallel between the terminals of the generating coil through which a current flows from the generating coil to the capacitor at the ignition timing and the ground. , a circuit is provided for supplying a signal having the same phase as the ignition timing signal to the generating coil short circuit thyristor. When the generating coil short-circuiting thyristor is conductive, the duration of the short-circuit current flowing from the generating coil side through the generating coil shorting thyristor is longer than the duration of the ignition timing signal and the duration of the group N current of the capacitor. The relationship between the ignition timing and the phase of the output voltage of the generating coil is set as follows.

Example The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 shows an embodiment of the present invention, in which the same parts as those in FIG. 1 are given the same reference numerals. The difference between the embodiment shown in FIG. 2 and the circuit shown in FIG. 1 is that among the non-grounded terminals 5a and 5b of the generating coil 5, the terminal 5b is the one through which the current flows to the capacitor 3 at the ignition timing of the engine. The point is that a generating coil short-circuiting thyristor 9 with its cathode facing the ground side is connected in parallel between the grounds. The gate of the thyristor 9 is connected to the output terminal of the signal supply circuit 7, and the ignition timing signal ig is applied to the gate of the thyristor.
An ignition signal igs having the same phase as the ignition signal igs is provided.

In the above embodiment, when the engine rotates, the generator coil 5
An alternating current voltage (e) as shown in FIG. 3a is induced. During a half cycle of this voltage in the direction of the arrow shown in the figure, the capacitor 3 is charged to the polarity shown in the figure from one coil 51 of the coils on both sides of the neutral point of the generator coil 5 through the diode 61, and then the capacitor 3 is charged to the polarity shown by the arrow of the voltage Ve. diode 62 from the other coil 52 in a half cycle in the opposite direction.
through which the capacitor 3 is charged again to the polarity shown.

Therefore, the voltage between the anode and cathode of the thyristor 4 (the voltage across the capacitor 3 > VC rises stepwise as shown in Figure 3. Near the fall of the half cycle of the voltage Ve in the direction opposite to the arrow shown in the figure) Set engine ignition timing t
At step i, an ignition timing signal ig having a waveform shown in FIG. 3C, for example, is supplied from the signal supply circuit 7 to the gate of the thyristor 4. Therefore, the thyristor 4 becomes conductive, and from the capacitor 3 to the thyristor 4 and the primary coil 1a of the ignition coil.
A discharge current ic flows through the capacitor as shown in FIG. 3d.

This induces a high voltage in the secondary coil of the ignition coil,
The engine is ignited. In the present invention, the ignition timing signal is applied to the thyristor 4 and at the same time the thyristor 9
ignition signal 1g5 (in this embodiment, ignition timing signal i
g) is given, the thyristor 9 becomes conductive, and the waveform shown in FIG.
A short circuit current is flows as shown in FIG. Due to the phase delay caused by the inductance of the generator coil, this short circuit current is continues to flow for a certain period of time even after the voltage ve rises in the direction of the arrow shown in the figure. No current is supplied. In the present invention, the end time t of this short circuit current is
The phase relationship is set so that ss is delayed in phase from the end time tsg of the ignition timing signal current 1g and the end time tsc of the discharge current IC of the capacitor 3.

That is, the duration of the ignition timing signal current 1g is tl,
When the duration of the discharge current IC is t2 and the duration of the short circuit current is is t3, t3 is set longer than both tl and t2. With this setting, the anode current of the discharge control thyristor 4 can be made zero after the discharge current becomes zero, so that the thyristor can be reliably set to p%.

In the above embodiment, the signal supply circuit 7 is connected to a signal coil 10 which is disposed in a signal generator driven by an engine and whose one end is grounded, and to a non-grounded terminal of the signal coil, as shown in FIG. 4, for example. It can be configured with diodes 11 and 12 whose anodes are commonly connected. In this case, the signal i
g and 1 gS. It is also possible to use a signal supply circuit provided with a circuit that shapes the output of the signal coil into a pulse waveform. Furthermore, there is a signal coil that generates a signal that determines the advance angle range in synchronization with the rotation of the engine, and an integral circuit that is controlled by the output of the signal coil and repeats an integral operation that charges the capacitor over a certain rotation angle range. By setting up
It is also possible to use an electronically controlled signal supply circuit that electronically generates an ignition timing signal having advance or retard characteristics by comparing the output voltage of the integrating circuit with a predetermined reference voltage.

FIG. 5 shows an embodiment of the present invention, and FIG. 6 shows signal waveforms at various parts of this embodiment. In this embodiment, a Zener diode 13 with its anode facing the gate is connected in parallel between the anode gates of the thyristor 9 for shorting the generating coil. In other respects, the structure is similar to that of the embodiment shown in FIG. In this embodiment, when the charging voltage of the capacitor 3 reaches the Zener voltage of the Zener diode 10 at time tc, the Zener diode 13 breaks down, and as shown in FIG. is applied and the thyristor becomes conductive. Therefore, the conduction of the thyristor 9 prevents charging of the capacitor 3, and the charging voltage of the capacitor is kept constant. Therefore, according to this embodiment, when the engine speed increases and the output voltage of the generator coil becomes high, it is possible to prevent the charging voltage of the capacitor 3 from becoming excessive.Other operations are shown in FIG. This is similar to the embodiment.

In the above embodiment, the power source is the power generation coil 5 which is grounded with the intermediate tap as the neutral point, but the present invention can be similarly applied to the case where a multi-phase power generation coil of three or more phases is used as the ignition power source coil. You can get 1 by applying it. For example, as shown in FIG. 7, a three-phase power generating coil 5 formed by connecting coils 51 to 53 in a star shape is used as a charging power source coil, and each coil 5
Connect diode 1 to each non-ground terminal of 1 to 53.
The anodes of the diodes 63 to 63 may be connected, and the cathodes of these diodes may be commonly connected to the connection point between the capacitor 3 and the anode of the thyristor 4.

In this case as well, the generating coil short-circuiting thyristor 9 may be connected between the ground and the non-grounded terminal of the coil 53 through which the current flows to the capacitor 3 at the ignition position.

In each of the above embodiments, only one generating coil short-circuiting thyristor 9 was provided, but as shown in FIG. You may also connect it. In this case, at the same time the ignition timing signal 1g is supplied from the signal supply circuit 7 to the gate of the thyristor 4, the ignition signals igs, igs'
is supplied to the gate of thyristor 9.9-.

Furthermore, in each of the above embodiments, a circuit was provided to directly supply an ignition signal from the signal supply circuit 7 to the thyristor for shorting the generating coil, but as shown in FIG. A diode 15 may be connected with the diode 15 facing the ground side, and a voltage drop across the diode may provide an ignition signal to the generating coil short-circuiting thyristor 9.

The full-wave rectifier circuit used in the present invention is not necessarily the one shown in each of the above embodiments (it is also possible to use a bridge-type full-wave rectifier circuit 6 consisting of diodes 61 to 64, as shown in FIG. You can also do that.

Effects of the Invention As described in 1, according to the present invention, by providing a generating coil short-circuiting thyristor and giving an ignition signal to the thyristor at the same time as the ignition timing signal, the period during which the anode current of the discharge control thyristor becomes zero can be reduced. I decided to create
There is an advantage that a full-wave rectifier circuit is used as a circuit for rectifying the output of the generating coil, and that the commutation of the discharge control thyristor can be reliably performed.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional example, Fig. 2 is a circuit diagram showing an embodiment of the present invention, Fig. 3 is a voltage and current waveform diagram of each part of the same embodiment, and Fig. 4 is a signal supply circuit diagram. Connection diagram showing an example,
Fig. 5 is a circuit diagram showing another embodiment of the present invention, Fig. 6 is a voltage or current waveform diagram of each part of the same embodiment, and Figs. FIG. 2 is a circuit diagram showing an example. DESCRIPTION OF SYMBOLS 1... Ignition coil, 2... Spark plug, 3... Capacitor for ignition energy storage, 4... Thyristor for discharge control, 5... Power generation coil, 61-64... Full-wave rectifier circuit 7... Signal supply circuit, 9.9'... Thyristor for shorting the generating coil.

Claims (1)

[Claims] A generator coil disposed in an alternator driven by an internal combustion engine, a rectifier circuit that full-wave rectifies the output of the generator coil, an ignition coil, and a rectifier circuit disposed on the primary side of the ignition coil. an ignition energy storage capacitor that is charged to one polarity by the output; a discharge control Nyristor that is provided so as to discharge the charge in the capacitor through the primary coil of the ignition coil when conductive, and whose cathode is grounded; In the capacitor discharge type ignition device for an internal combustion engine, comprising a signal supply circuit that supplies an ignition timing signal to the gate of the discharge control silisk at the ignition timing of the internal combustion engine, the capacitor discharge type ignition device includes a signal supply circuit that supplies an ignition timing signal to the gate of the discharge control silisk at the ignition timing of the internal combustion engine. a generating coil short-circuiting thyristor connected in parallel between a terminal through which a current flows from the generating coil to the capacitor side and the ground, with the cathode facing the grounding side;
a circuit for supplying a signal having the same phase as the ignition timing signal to the generating coil short-circuiting thyristor; The relationship between the ignition timing and the phase of the output voltage of the generating coil is set so that the duration is longer than the duration of the ignition timing signal and the duration of the discharge current of the capacitor. Capacitor discharge type ignition system for internal combustion engines.