JPH0467589B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a current interrupt type ignition device for an internal combustion engine.

[Prior Art] A current interrupt type ignition device for an internal combustion engine includes an ignition coil, an ignition power supply coil that is provided on the primary side of the ignition coil and induces an alternating current voltage in synchronization with the rotation of the internal combustion engine, and an ignition power supply. The collector-emitter circuit is connected in parallel to the coil, and the primary current control transistor switch circuit conducts when a half-cycle voltage of one polarity is induced in the ignition power supply coil. It is composed of a cut-off control switch circuit provided to cut off the control transistor switch circuit, and a cut-off control switch trigger circuit that conducts the cut-off control switch circuit at the ignition timing of the internal combustion engine. The voltage induced in the ignition power supply coil when the control transistor switch circuit is cut off is boosted by the ignition coil to obtain a high voltage for ignition.

[Problems to be Solved by the Invention] A current interrupting type ignition device for internal combustion engines as described above was provided with an advance function, as disclosed in
There is an ignition device shown in No. 33590, but this type of ignition device has a problem in that it is difficult to set the advance starting rotation speed.

An object of the present invention is to provide a current interrupting type ignition device for an internal combustion engine that can easily set an advance starting rotation speed.

[Means for Solving the Problems] In the present invention, the cutoff control switch trigger circuit that triggers the cutoff control switch circuit at the ignition timing of the internal combustion engine includes a voltage dividing circuit connected to both ends of the ignition power supply coil. An ignition timing control capacitor is connected in parallel between the trigger signal input terminals of the cutoff control switch circuit and charged with the output voltage of the voltage dividing circuit, and when the terminal voltage of the capacitor reaches the trigger level. A trigger signal supply circuit for supplying a trigger signal to a cut-off control switch circuit, and a switch means connected in series or parallel to a part of the voltage dividing circuit, and charging of an ignition timing control capacitor by the operation of the switch means. A voltage division ratio control circuit that changes the voltage division ratio of the voltage division circuit so as to accelerate the speed detection capacitor and a speed detection capacitor that is charged by the output voltage of the other polarity half cycle of the ignition power supply coil with a fixed time constant. When the terminal voltage of the speed detection capacitor exceeds the set value at the time when the discharging resistor and the ignition power supply coil generate a half-cycle output voltage of one polarity, the terminal voltage of the speed detection capacitor becomes higher than the set value. A switch means control circuit is provided to operate the switch means during a period when the value exceeds a set value.

[Operation of the invention] In the above-mentioned ignition device for an internal combustion engine, when the rotational speed of the internal combustion engine is less than the advance start rotational speed, when the ignition power supply coil generates an output voltage of a half cycle of one polarity, the speed detection Since the terminal voltage of the capacitor is less than the set value, the switching means of the voltage division ratio control circuit does not operate. At this time, the terminal voltage of the ignition timing control capacitor reaches the trigger level at the low speed ignition timing, triggers the cutoff control switch circuit, and puts the primary current control transistor switch circuit in the cutoff state. This induces a voltage in the ignition power supply coil, and this voltage is boosted by the ignition coil to obtain a high voltage for ignition on the secondary side of the ignition coil.

When the rotation speed of the internal combustion engine reaches the advance start rotation speed, the voltage at the terminals of the speed detection capacitor exceeds the set value when the ignition power supply coil induces a voltage of one polarity. At this time, only during the period when the terminal voltage of the speed detection capacitor exceeds the set value, the switching means of the voltage division ratio control circuit operates to accelerate the charging speed of the ignition timing control capacitor.
When the terminal voltage of the speed detection capacitor becomes less than the set value, the charging speed of the ignition timing control capacitor is returned to the original value. Therefore, the terminal voltage of the ignition timing control capacitor reaches the set value earlier, the primary current control transistor switch circuit is cut off earlier, and the ignition timing is advanced.

When the rotation speed of the internal combustion engine reaches the advance end rotation speed and the terminal voltage of the speed detection capacitor drops to the set value, the terminal voltage of the ignition timing control capacitor reaches a level that triggers the cut-off control switch circuit. When the terminal voltage of the speed detection capacitor drops to the set value, the primary current control transistor switch circuit is cut off and the ignition operation is performed. When the rotational speed of the internal combustion engine further increases, the terminal voltage of the speed detection capacitor reaches the set level while the switching means of the voltage division ratio control circuit is operating. As a result, the ignition timing becomes almost constant.

As described above, according to the present invention, a current interrupt type ignition device for an internal combustion engine can be provided with an advance function with a relatively simple configuration. Particularly in the present invention, when the resistance value of the discharge resistor is decreased, the advance angle start rotation speed becomes high, and when the resistance value of the discharge resistor is increased, the advance angle start rotation speed is decreased. Therefore, by adjusting the resistance value of this discharge resistor, the advance start rotation speed can be easily adjusted.

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

FIG. 1 shows a schematic configuration of an embodiment of the present invention. In the figure, 1 is an ignition coil having a primary coil 1a that also serves as an ignition power supply coil and a secondary coil 1b, and 2 is for primary current control. A transistor switch circuit, 3 is a cut-off control switch circuit that controls the primary current control transistor switch circuit to be cut off at the ignition timing of the internal combustion engine, and 4 is a cut-off control switch circuit that controls the voltage across the ignition power supply coil (primary coil). Ignition timing control capacitor C is connected between the voltage dividing circuit 4a that divides the voltage and the trigger signal input terminal of the cutoff control switch circuit and is charged by the output of the voltage dividing circuit 4a.
1, a trigger signal supply circuit for supplying a trigger signal to the cut-off control switch circuit when the terminal voltage of the capacitor C1 exceeds a predetermined trigger level; 5, a switch means 5a for operating the switch means; 6 is a voltage division ratio control circuit that controls the voltage division ratio of the voltage division circuit 4a of the trigger signal supply circuit 4 so as to accelerate the charging of the ignition timing control capacitor; 6 is a switch of the voltage division ratio control circuit 5 according to the rotational speed of the internal combustion engine; A switch means control circuit 7 for controlling the means 5a is an ignition plug attached to a cylinder of an internal combustion engine (not shown) and whose non-grounded terminal is connected to a secondary coil of an ignition coil via a high voltage cord. In this embodiment, a trigger signal supply circuit 4, a voltage division ratio control circuit 5, and a switch means control circuit 6 constitute a switch trigger circuit for cut-off control.

More specifically, the ignition coil 1 has at least its primary coil 1a installed in a magnet generator driven by an internal combustion engine, and induces an alternating current voltage in the primary coil 1a in synchronization with the rotation of the internal combustion engine. . That is, in this embodiment, one of the ignition coils
The secondary coil 1a also serves as an ignition power supply coil.

The transistor switch circuit 2 for primary current control is connected to the darlington, and the collector is connected to the ignition coil 1.
It consists of a composite transistor Tr1 which is grounded together with one end of the primary coil, and resistors R1 and R2,
The emitter of transistor Tr1 is the primary coil 1a
Connected to the other end (non-ground terminal). The base of the transistor Tr1 is connected to one end of a resistor R1, and a resistor R2 is connected between the other end of the resistor R1 and ground. When the ignition power supply coil 1a induces a half-cycle voltage of one polarity in the direction of the arrow shown in the figure, the transistor Tr1 conducts as a base current is applied through the resistors R2 and R1. A short circuit current flows between the collector and emitter of the transistor Tr1.

The cutoff control switch circuit 3 is a transistor whose emitter is connected to the non-ground terminal of the primary coil 1a.
The collector of the transistor Tr2 is connected to the connection point between the resistors R1 and R2.

The trigger signal supply circuit 4 consists of an ignition timing control capacitor C1, resistors R3 to R6, and a diode D1. between the base emitters)
are connected in parallel. Resistors R4 to R6 are connected in series to form a voltage dividing circuit 4a, and this voltage dividing circuit 4a is connected in parallel to both ends of the primary coil (ignition power supply coil) 1a of the ignition coil.
The connection point (voltage dividing point) between 5 and R6 is the diode D1.
Ignition timing control capacitor C1 and resistor R
It is connected to the connection point with 3. Capacitor C1
is the voltage across the ignition power supply coil 1a and the voltage divider circuit 4
When the terminal voltage of this capacitor C1 reaches a predetermined trigger level, the transistor Tr2 becomes conductive. When the transistor Tr2 becomes conductive, the base current of the transistor Tr1 is bypassed from the transistor Tr1, so that the transistor Tr1 is turned off. When the transistor Tr1 is cut off, the short-circuit current flowing from the ignition power supply coil 1a through the collector-emitter of the transistor Tr1 is cut off, so a high voltage is induced in the ignition power supply coil 1a, and this voltage is further applied by the ignition coil. The voltage is increased and a high voltage for ignition is induced in the secondary coil 1b of the ignition coil. Since this high voltage is applied to the ignition plug 7, a spark is generated in the ignition plug and the engine is ignited.

The voltage division ratio control circuit 5 includes a switch means 5a,
The switch means 5a of this embodiment is a normally open switch, and is connected in parallel to a resistor R5 of a portion of the voltage dividing circuit 4a of the trigger signal supply circuit 4. The switch means control circuit 6 detects the rotational speed of the internal combustion engine and controls the switch means 5a to close for a certain period of time when the rotational speed exceeds the advance start rotational speed. When the switch means 5a is closed, the resistor R5 is short-circuited, so that the ignition timing control capacitor C1 is charged faster, and when the switch means 5a is opened, the charging time constant of the capacitor C1 is returned to the original value. As described above, when the switch means 5a is closed, the capacitor C1 receives power earlier, so that the phase in which the terminal voltage of the capacitor C1 reaches the trigger level of the transistor Tr2 advances, and the ignition timing is advanced.

FIG. 2 shows another embodiment of the present invention,
In this embodiment, the voltage dividing circuit 4a includes resistors R4 and R6.
It is made up of The voltage division ratio control circuit 5 includes a resistor R5 and a switch means 5a, and a series circuit of the resistor R5 and the switch means 5a is connected in parallel to both ends of the resistor R4. In other respects, the structure is similar to that of the embodiment shown in FIG.

In the embodiment shown in FIG. 2, when the switch means 5a is closed, the resistor R5 is connected in parallel to the resistor R4, so that the charging time constant of the capacitor C1 becomes small.

FIG. 3 shows still another embodiment of the present invention, in which the voltage dividing circuit 4a is constructed in the same manner as in FIG. Means 5b is connected. The switch means control circuit 6 opens the switch means 5b for a certain period of time when the rotation speed of the internal combustion engine exceeds the advance start rotation speed.

In the embodiment of FIG. 3, when the switch means 5b is opened, the resistor R6 is connected in series with the resistor R5 of the voltage divider circuit 4a, so that the output voltage of the voltage divider circuit 4a (the voltage across resistors R5 and R6) increases, accelerating the charging of capacitor C1.

FIG. 4 shows still another embodiment of the present invention, in which the voltage dividing circuit 4a is connected to the resistors R4 and R
5, and the voltage division ratio control circuit 5 consists of a resistor R6 and a switch means 5b consisting of a normally closed switch. The resistor R6 is connected in series with the switch means 5b, and the series circuit of the resistor R6 and the switch means 5b is connected in parallel with the resistor R5. The switch means control circuit 6 opens the switch means 5b for a certain period of time when the rotation speed of the internal combustion engine exceeds the advance start rotation speed.

In the embodiment of FIG. 4, when the switch means 5b is opened, the resistor R6 is disconnected from the resistor R5 of the voltage divider circuit 4a, so that the output voltage of the voltage divider circuit 4a increases and the charging of the capacitor C1 is accelerated.

In each of the above embodiments, the cutoff control switch 3 is composed of the transistor Tr2, but as shown in FIG.
can also be configured by a thyristor S1, in which case the gate and cathode of the thyristor S1 serve as trigger signal input terminals.

Next, a more specific embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 shows an embodiment embodying the configuration of FIG. 1. In this embodiment, the transistor of the cutoff control switch circuit 3
A protection diode D2 is connected in parallel between the collector and emitter of the Tr2, and a diode D3 with its anode facing the ground is inserted between the resistor R4 of the voltage dividing circuit 4a and the ground terminal. The switching means 5a is composed of a transistor Tr3 having a collector-emitter circuit connected in parallel to both ends of a resistor R5, and a transistor Tr4 having a collector connected to the base of the transistor Tr3 via a resistor R7.
The emitter of the transistor Tr4 is connected to the non-ground terminal of the ignition power supply coil 1a.

The switch means control circuit 6 consists of a speed detection capacitor C2, diodes D4 and D5, a Zener diode Z1, and resistors R8 and R9. One end of the speed detection capacitor C2 is connected to the non-ground terminal of the ignition power supply coil 1a through a diode D4 whose cathode faces the capacitor, and the other end is connected to the ground terminal through a diode D5 whose anode faces the capacitor. It is connected. The diode D4 side terminal of the capacitor C2 is connected to the transistor via the Zener diode Z1.
It is connected to the base of Tr4, and a discharge resistor R8 is connected in parallel to both ends of the capacitor C2. Further, a resistor R9 is connected in parallel to both ends of the series circuit of the diode D4 and the capacitor C2.

In the embodiment of FIG. 6, in the negative half cycle of the primary coil 1a, diodes D4 and D
5, the speed detection capacitor C2 is charged to the polarity shown in the figure, and when the induced voltage of the negative half cycle of the primary coil 1a passes the peak, this capacitor C2 is charged to the polarity shown in the figure.
2 charges are discharged through resistor R8 with a constant time constant. The rotational speed of the internal combustion engine is the advance starting rotational speed N.
1, the terminal voltage V2 of the capacitor C2 becomes the Zener voltage of the Zener diode Z1 at the beginning of the positive half cycle of the output voltage V1 of the primary coil 1a, as indicated by the symbol in FIG. 8b.
Since it is less than Vz1, no base current is applied to the transistor Tr4 at the time when the output voltage of the positive half cycle of the primary coil 1a rises. Therefore, at this time, the transistor Tr3 is not conductive, and the voltage division ratio control circuit 5 has no effect on the charging of the capacitor C1. At this time, the capacitor C1 is charged to the polarity shown in the figure by the output voltage of the voltage dividing circuit 4a consisting of resistors R4, R5, and R6. Furthermore, when the primary coil (ignition power supply coil) 1a induces a positive half-cycle voltage, the base current flows to the transistor Tr1 and the transistor Tr1 becomes conductive.
A short-circuit current flows between the collector and emitter of 1. Then, when the terminal voltage of capacitor C1 exceeds the predetermined trigger level Vt at the position of angle θ1,
Transistor Tr2 becomes conductive and transistor Tr1
into the cut-off state. This induces a high voltage in the secondary coil of the ignition coil, igniting the engine.

When the rotation speed of the internal combustion engine reaches the advance start rotation speed N1, when the positive half cycle of the primary coil 1a starts, the terminal voltage V2 of the capacitor C2 becomes equal to the Zener voltage Vz1 of the Zener diode Z1, and further For example, if the rotation speed increases
2, it becomes 1 as indicated by the symbol in Figure 8b.
When the output voltage of the next positive half cycle of the coil 1a rises, the terminal voltage V2 of the capacitor C2 becomes equal to or higher than the Zener voltage Vz1 of the Zener diode Z1. In such a situation, 1
Next, when the output voltage of the positive half cycle of the coil 1a rises, the capacitor C2 is discharged through the Zener diode Z1, the base emitter of the transistor Tr4, and the resistor R9.
Since the base current is flowing through 4, the primary coil 1
At the same time as the output voltage of the positive half cycle of a rises, transistor Tr4 becomes conductive, and this transistor
Due to the conduction of Tr4, a base current flows through the transistor Tr3, and the transistor Tr3 becomes conductive. Since both ends of the resistor R5 are short-circuited by the conduction of the transistor Tr3, the charging time constant of the capacitor C1 becomes small, and the capacitor C1 is charged quickly. When the terminal voltage of capacitor C2 becomes less than Zener voltage Vz1 of Zener diode Z1,
Since the transistor Tr4 is cut off, the transistor Tr3 is also cut off, and the short circuit of the resistor R5 is released. Therefore, the charging time constant of the capacitor C1 returns to the original state, and the capacitor C1 is once again charged with the time constant determined by the voltage dividing circuit 4a consisting of resistors R4 to R6. When the terminal voltage of capacitor C1 reaches the trigger level of transistor Tr2, transistor Tr2 becomes conductive and the transistor
Tr1 is cut off, but in this case, for a certain period α1 after the output voltage of the positive half cycle of the primary coil 1a rises (the terminal voltage of the capacitor C2 exceeds the Zener voltage of the Zener diode Z1). Since the charging time constant of the capacitor C1 is reduced, the phase in which the terminal voltage of the capacitor C1 reaches the trigger level of the transistor Tr2 advances, and the ignition timing is advanced to θ2. The terminal voltage of capacitor C2 is Zener diode Z1
The period (angle) during which the Zener voltage Vz1 is higher than Vz1 becomes longer as the rotational speed of the internal combustion engine increases, so the ignition timing advances as the rotational speed increases during the period.

When the rotational speed of the internal combustion engine reaches the advance end rotational speed N3, the capacitor C2 is connected to the Zener diode Z for a period α2, as indicated by the symbol in FIG. 8b.
The terminal voltage of the capacitor C1 reaches the trigger level Vt at the moment when the Zener voltage Vz1 becomes higher than the Zener voltage Vz1 of 1, and the period α2 has elapsed at the angle θ3. Therefore, the angle θ
The engine is ignited in position 3. When the rotational speed of the internal combustion engine further increases, the terminal voltage V3 of the capacitor C1 reaches the trigger level Vt of the transistor Tr2 while the transistor Tr3 is conducting, so the ignition timing becomes approximately constant (=θ3). Therefore, the characteristics of the ignition timing with respect to the rotation speed N of the internal combustion engine are as shown in FIG. 9, and a characteristic is obtained in which the ignition timing is advanced from the advance start rotation speed N1 to the advance end rotation speed N3.

The advance start rotation speed N1 can be adjusted as appropriate by adjusting the resistance value of the discharge resistor R8 connected to both ends of the speed detection capacitor C2. That is, by decreasing the resistance value of the resistor R8, the advance angle start rotation speed can be increased, and by increasing the resistance value of the resistor R8, the advance angle start rotation speed can be decreased.

FIG. 7 shows an embodiment embodying the configuration of FIG. 4. In this embodiment, the switching means 5b of the voltage division ratio control circuit 5 consists of a field effect transistor F1, and the source of this field effect transistor is
The drain is connected to the non-grounded terminal of the next coil (ignition power supply coil) 1a, and to the connection point (voltage division point) between resistors R4 and R5 via a resistor R6. The switch means control circuit 6 is a capacitor C2.
, resistors R7 and R8, a Zener diode Z1, and a diode D4, and the speed detection capacitor C2 is a diode D with its cathode facing the ground side.
4 in parallel to the primary coil 1a. The discharge resistor R8 is connected in parallel to both ends of the capacitor C2, and the connection point between the capacitor C2 and the anode of the diode D4 is connected to the gate of the field effect transistor F1 via the Zener diode Z1. A resistor R7 is connected in parallel between the gate and source of the field effect transistor F1.

In the embodiment shown in FIG. 7, when the rotation speed of the internal combustion engine is less than the advance start rotation speed, the terminal voltage of the capacitor C2 changes to the Zener diode Z1 at the time when the positive half cycle of the primary coil 1a starts. Since the voltage is less than Vz1, the field effect transistor F1 remains conductive, and the resistor R6 is connected in parallel to the resistor R5. At this time, capacitor C1 is connected to resistor R4 and resistor R5.
and R6, and the ignition operation is performed at a delayed position. When the rotation speed exceeds the advance angle start rotation speed, 1
Next, at the start of the positive half cycle of the coil 1a, the terminal voltage of the capacitor C2 becomes higher than the Zener voltage Vz1 of the Zener diode Z1, so the terminal voltage of the capacitor C2 passes through the Zener diode Z1 to the gate of the field effect transistor F1. It is applied between the sources, and the gate-source voltage of the field effect transistor F1 becomes higher than the cut-off voltage. This causes the field effect transistor F1 to be turned off and the resistor R6 to be disconnected from the resistor R5. Therefore, the output voltage of the voltage dividing circuit 4a increases, the charging of the capacitor C1 is accelerated, and the ignition timing is advanced.

In the above embodiment, at least the primary coil 1a of the ignition coil 1 is provided inside the magnet generator, and this primary coil 1a also serves as the ignition power supply coil, but the ignition coil 1 is installed outside the magnet generator. Of course, the present invention can also be applied to the case where an exciter coil provided in a magnet generator is used as an ignition power supply coil. In this case, the exciter coil is connected in parallel to the primary coil of the ignition coil, and the transistor Tr1 of the primary current control transistor switch circuit 2 is connected in parallel to the primary coil of the ignition coil.
A collector-emitter circuit is connected in parallel to the exciter coil.

[Effects of the Invention] As described above, according to the present invention, since the ignition timing control capacitor is rapidly charged for a certain period of time in the rotation speed region equal to or higher than the advance start rotation speed, a particularly complicated circuit configuration is not required. It is possible to have an advance angle function without having to change the angle. Further, there is an advantage that the advancing start rotation speed can be easily adjusted by adjusting the discharge time constant of the rotation speed detection capacitor.

[Brief explanation of drawings]

1 to 4 are circuit diagrams showing schematic configurations of different embodiments of the present invention, FIG. 5 is a circuit diagram of the main part showing a modification of the cut-off control switch circuit used in the present invention, and FIG. 7 and 7 are circuit diagrams showing different specific embodiments of the present invention, FIG. 8 is a voltage waveform diagram of each part of FIG. 6, and FIG. 9 is a lead angle characteristic obtained by the device of the present invention. It is a line diagram showing an example. DESCRIPTION OF SYMBOLS 1... Ignition coil, 1a... Primary coil (ignition power supply coil), 1b... Secondary coil, 2... Transistor switch circuit for primary current control, 3... Switch circuit for cutoff control, 4... Trigger signal supply circuit, 5... Division ratio control circuit, 5a, 5b... switch means, 6... switch means control circuit, 7... spark plug, C1... capacitor for ignition timing control, C2... capacitor for speed detection.

Claims (1)

[Scope of Claims] 1. An ignition coil, an ignition power supply coil that is provided on the primary side of the ignition coil and induces an alternating current voltage in synchronization with the rotation of the internal combustion engine, and a collector emitter for the ignition power supply coil. a primary current control transistor switch circuit which is connected in parallel and becomes conductive when a half-cycle voltage of one polarity is induced in the ignition power supply coil;
A cut-off control switch circuit provided to place the next current control transistor switch circuit in a cut-off state; and a cut-off control switch trigger circuit that conducts the cut-off control switch circuit at the ignition timing of the internal combustion engine; In an ignition device for an internal combustion engine that obtains a high voltage for ignition by boosting the voltage induced in the ignition power supply coil by the ignition coil when the primary current control transistor switch circuit is cut off, the cutoff control switch trigger circuit comprises: an ignition timing control capacitor connected in parallel between a voltage dividing circuit connected to both ends of the ignition power supply coil and a trigger signal input terminal of the cutoff control switch circuit and charged with the output voltage of the voltage dividing circuit; a trigger signal supply circuit that supplies a trigger signal to the cutoff control switch circuit when the terminal voltage of the capacitor reaches the trigger level; and a trigger signal supply circuit connected in series or parallel to a part of the voltage divider circuit. a voltage division ratio control circuit comprising a switch means and changing the voltage division ratio of the voltage divider circuit so as to accelerate charging of the ignition timing control capacitor by the operation of the switch means; and a half cycle of the other polarity of the ignition power supply coil. The speed detection capacitor charged by the output voltage of It is characterized by comprising a switch means control circuit that operates the switch means during a period when the terminal voltage of the speed detection capacitor is equal to or higher than the set value when the terminal voltage of the detection capacitor is equal to or higher than the set value. Ignition system for internal combustion engines. 2. The ignition coil has at least its primary coil installed in a magnet generator driven by an internal combustion engine, and the primary coil of the ignition coil also serves as the ignition power supply coil. The ignition device for an internal combustion engine according to scope 1. 3. The internal combustion engine according to claim 1, wherein the ignition coil is provided outside a magnet generator driven by an internal combustion engine, and the ignition power supply coil is provided inside the magnet generator. Engine ignition system.