JPS5941669A - Capacitor discharge type ignition system in internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent delays in the ignition timing of an engine upon the high- speed running of the engine and the generation of sparks upon the reverse revolution of the engine, with a simple construction, by connecting a signal control circuit comprising a signal control capacitor, a thyristor, etc., to a discharge controlling thyristor in a capacitor discharged type ignition system in the engine. CONSTITUTION:An exciter coil 1 is disposed in a magnet generator which rotates in synchronism with an engine so that first, second and third half-cycle voltages having alternately different polarilities, are successively generated. Further, there is provided a signal control circuit 11 for controlling the supply of signals to a discharge controlling thyristor 9 for controlling the discharge of a condensor 7. This circuit 11 comprises a signal controlling thyristor 9 for short-circuiting the negative output voltage of the above-mentioned coil 1 upon the energization of the thyristor 12, a signal control capacitor 14 which is discharged with the positive output voltage of the above-mentioned coil 1 and a discharge circuit 20 for discharging the capacitor 14. Further, a current limiting resistor 21 is disposed in the path of current which runs through the anode and cathode of the thyristor 12 from the coil 1.

Description

[Detailed description of the invention] This invention relates to an electric internal combustion engine ignition system.

As a capacitor discharge type internal combustion engine ignition system, a capacitor is charged by the positive half-cycle output of an exciter coil installed in the magnet generator, and a discharge control thyristor is charged by the negative half-cycle output generated from the exciter coil. There is a device that performs ignition by applying an ignition signal to the thyristor and discharging the charge in the capacitor to the primary coil of the ignition coil through the thyristor. According to such a configuration, the structure of the generator attached to the engine can be simplified, since the Shingetsu coil for determining the ignition position is not required. However, in conventional ignition devices of this type, the rise of the output in the next negative half cycle is delayed due to the armature reaction caused by the current flowing from the exciter coil to the capacitor during the positive half cycle of the exciter coil, resulting in a delay in the ignition position. There was a problem that occurred. This tendency becomes more pronounced as the engine speed (rpm) increases, and in the conventional ignition system of this type, the characteristic of the engine ignition position θi with respect to the engine speed N is as shown by the broken line in Fig. 5. This had the disadvantage that the ignition position was significantly delayed at high speeds. The ignition position θ1 on the vertical axis in FIG. 5 indicates the angle before the top dead center of the engine, with O being the ignition position at the normal rotation speed (3000 rpm).

With this kind of conventional ignition system, the ignition signal is sent to the capacitor discharge thyristor even when the engine is rotating in reverse, so the engine will not be ignited even when the engine is rotating in reverse.
It was unsuitable as an ignition system for a two-cycle engine.

SUMMARY OF THE INVENTION An object of the present invention is to provide a capacitor discharge type internal combustion engine ignition system that has a simple configuration that does not use a signal coil, and that can prevent delays in ignition position at high speeds and generation of sparks during reverse rotation. .

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below along with embodiments thereof with reference to the drawings.

FIG. 1 shows a circuit according to an embodiment of the present invention, in which 1 is an exciter coil arranged in a magnet generator that rotates synchronously with the internal combustion engine, 2 is a primary coil 2a and 2
This is an ignition coil that starts from the secondary coil 2b, and one ends of the primary and secondary coils 2a and 2b of the ignition coil are commonly connected and grounded. 3 is an ignition plug connected to a secondary coil 2b, and this ignition plug is attached to a cylinder of an engine (not shown). The cathodes of diodes 4 and 5 are connected to one end 1a and the other end 1b of the exciter coil 1, respectively, and the anodes of these diodes are grounded. There is also a diode 6 at one end of the exciter coil 1.
The anode of this diode is connected, and the cathode of this diode is connected to one end of the ignition energy storage capacitor 7. The other end of the capacitor 7 is connected to the non-ground terminal of the primary coil 2a of the ignition coil, and is also connected to the damper diode 8.
The cathode of the diode 8 is grounded. The anode of a discharge control thyristor 9 is connected to the connection point between the cathode of the diode 6 and the capacitor 7, and the cathode of the thyristor 90 is grounded. The anode of a Zener diode 10 is connected to the dart of the thyristor 9, and the cathode of the Zener diode 10 is connected to the other end 1b of the exciter coil 1 via a current limiter t121f. In this embodiment, the diode 4, the Zener diode 10, and the current limiting resistor 21 constitute a signal supply circuit that provides an ignition signal to the thyristor 9 using the negative half-cycle output of the exciter coil 1. When the output voltage in the direction of the dashed arrow (5) shown in the figure becomes equal to or higher than the Zener level of the Zener diode 10, the exciter coil 1 → current limiting resistor 21 → Zener diode 10 →
'-tocathode → diode 4 → exciter coil 1
An ignition signal is given to the thyristor 9 through the path. In this specification, the polarity of the output of the exciter coil is such that the polarity of the half cycle in which the capacitor 7 is charged is positive, and the polarity in the half cycle in which the ignition signal is given to the thyristor 9 is negative.

A signal control circuit 11 is provided to control the supply of signals to the thyristor 9. This control circuit includes a thyristor 12 whose anode is connected to the other end 1b of the exciter coil 1, and the cathode of the thyristor 12 is grounded via a resistor 13 having a small resistance value. Thyristor 1
2 is provided to substantially short-circuit the negative output voltage of the exciter coil 1 when conduction occurs, and the anode and cathode are biased in the forward direction by the negative output voltage of the exciter coil 1, and conduction occurs. The state becomes possible (6). The control circuit 11 includes a signal control capacitor 14 whose one end is grounded, and the other end of the capacitor 14 is connected to the gate of the thyristor 12 via a resistor 15. A cathode of a diode 17 is connected to the connection point of the exciter coil 1 via a resistor 16, and an anode of the diode 17 is connected to one end 1 of the exciter coil 1.
connected to a. Therefore, the signal control capacitor 14 is charged to the polarity shown in the figure through the diode 17 and the resistor 6 by the positive output of the exciter coil 1 (the output V2 in the direction of the solid arrow in the figure). Resistor 15 and 1
3 constitutes a first discharge circuit that discharges the capacitor 14 through between the gate and cathode of the thyristor 12,
The capacitor 14 is discharged along a path from the resistor 15 to the gate and cathode of the thyristor 12 to the resistor 13 to the capacitor 14, so that an ignition signal is given to the thyristor 12.

The collector of a transistor 18 whose emitter is grounded is connected to one end of the non-grounded side of the capacitor 14, and the base of the transistor 18 is connected to the non-grounded terminal of the resistor 13 through a resistor 19. Transistor 8 is for discharging the capacitor 14, and the transistor 18 and resistors 19 and 13 form a second discharge circuit 1 that discharges the capacitor 14 while the thyristor 12 is conducting.
．． 20 are configured.

In the ignition device of the above embodiment, the exciter coil 1 is
When the engine rotates in the positive direction, during one rotation of the rotor, the first half-cycle of the phone VT of negative polarity and the second half of the positive polarity.
A half-cycle voltage v2 and a third half-cycle voltage v3 of negative polarity are sequentially generated.

FIG. 2 shows an example of a magnet generator that generates such a voltage in an exciter coil, and this magnet generator consists of a magnet rotor 30 and a stator 40. The magnet rotor 30 consists of a rotor body 31 made of a magnetic material and a magnet 33 fixed in a recess 32 provided on the outer periphery of the rotor body 31. It has a shaft mounting hole 34 into which a drive shaft such as a shaft is fitted. The magnet 33 is magnetized in the radial direction of the rotor.
The magnetic pole 33a on the outer circumferential side of 3 (N pole in the example shown) and the recess 3
Magnetic poles (S poles in the example shown) appearing on both sides of 2 33
b and 33c constitute three rotor magnetic poles.

The stator 40 includes a laminated iron core 41 formed in a substantially U-shape, and the ends of both leg portions 42 and 43 of this iron core 41 have magnetic pole portions 44 and 45 that face the magnetic poles of the rotor with a predetermined gap therebetween. It is formed.

The spacing between the magnetic pole parts 44 and 45 of the iron core 41 is set approximately equal to the spacing between the magnetic poles 33b and 33c of the rotor, and the magnetic pole parts 44 and 45 are set to be approximately equal to the spacing between the magnetic poles 33b and 33c of the rotor.
It is possible to face each at the same time. iron core 4
The primary coil 2a and the secondary coil 2 are attached to one leg 42 of the
An ignition coil 2 consisting of b is wound therein, and an exciter coil 1 is also wound thereon. In this generator, when the engine rotates in the forward direction and the rotor 30 rotates in the forward clockwise direction in FIG. 2, the induced voltage waveform of the exciter coil 1 is shown with respect to the rotation angle θ as shown in FIG. become that way. This induced voltage has a waveform in which negative polarity voltage v1, (9) positive polarity voltage v2, and negative polarity voltage v3 appear in sequence, and is generated once per ignition cycle. Here, one ignition cycle is the period from one ignition in the engine cylinder until the next ignition, and in the example shown in FIG. are equal. Further, in FIG. 2, the waveform of the induced voltage in the exciter coil 1 when the magnet rotor 30 rotates in the counterclockwise direction is as shown in FIG. 3(b), and the positive half-cycle voltage v3' and the negative half-cycle voltage v! ' and a half-cycle voltage v1' of positive polarity appear in sequence.

In the example shown in FIG. 2, since the ignition coil 2 is wound around the stator core 41, a voltage is also induced in the ignition coil 2 due to the rotation of the rotor 30. In this embodiment, the ignition coil 2
A voltage having a phase opposite to the output voltage of the exciter coil 1 is induced in the primary coil 2a of the exciter coil 1. That is, in FIG. 1, when a positive voltage v2 in the direction of the solid arrow is induced in the exciter coil 1, a negative voltage in the direction of the solid arrow (10) is induced in the primary coil 2a. It should be noted that the ignition coil 2 does not necessarily need to be installed inside the magnet generator.
It may be provided outside the magnet generator.

Next, the operation of the above embodiment will be explained. When the rotor 30 of the magnet generator shown in FIG. 2 rotates in the forward direction, a voltage is induced in the exhaust coil l that exhibits an angleless waveform as shown in FIG. 4(a) with respect to the rotation angle θ. This waveform is similar to that shown in FIG. 3(,). Exciter coil 1 at angle θl
When a positive half-cycle voltage v2 is induced in , current flows through the paths of exciter coil 1 → diode 6 → capacitor 7 → diode 8 and primary coil 2a → diode 5 → exciter coil 1, and capacitor 7 has the polarity shown. It will be charged. At this time, the terminal voltage of capacitor 7 is
It changes as shown in figure (b). Also, this positive polarity voltage v2
Diode 1" 17, resistor 16. Capacitor 1
4 and the diode 5, and the signal control capacitor 14 is charged to the polarity shown. The charge on this capacitor 14 is transferred to the resistor 15. In order to discharge between the y-tocathode of the thyristor 12 and through the resistor 13, the angle θ
At the same time as the voltage v3 of negative polarity is induced in the exciter coil 1 at step 2, the thyristor 12 becomes conductive. When the thyristor 12 becomes conductive, the flow from the exciter coil 1 to the thyristor 12. Resistor 21 and Resistor 1
A current lb flows through 3 through 1, and the exciter coil 1 is substantially short-circuited. Therefore the Zener diode 10
The voltage applied to the diode 5 (voltage v0 across the diode 5) is at the Zener level Vz, as shown by the solid line in FIG. 4(c).
The value becomes lower, and no firing signal is given to the thyristor 9.

The current 1b flows due to the armature reaction to a position that is delayed by υ from the fall position of the waveform of the voltage v3 when no load is applied. When the thyristor 12 becomes conductive, a voltage drop occurs across the resistor 130, and this voltage causes the transistor 1 to pass through the resistor 19.
A pace current flows through 8. Therefore transistor 18
becomes conductive, and the charge in the capacitor 14 is discharged through the collector-emitter of the transistor 18. The thyristor 12u remains conductive while the exciter coil generates the negative voltage v3, and the pace current continues to be supplied to the transistor 18 during this time, so the capacitor 1
4 is completely discharged by the end of the half cycle of the negative polarity voltage v3. Next, a first half-cycle voltage v1 of negative polarity is induced in the exciter coil 1 at an angle θ4, but at this time there is no charge in the capacitor 4, and unless an ignition signal is given to the thyristor 12, the thyristor 12 is cut off. held in state. Therefore, the instantaneous value of the negative polarity voltage V4 increases, and when the voltage vc applied to the Zener diode 10 reaches or exceeds the Zener level at the angle θi, the
An ignition signal is given to the ignition signal. As a result, the thyristor 9 becomes conductive, and the charge in the capacitor 7 is rapidly discharged through the thyristor 9 and the primary coil 2a.

This discharge current causes a large magnetic flux change in the iron core of the ignition coil 2, which induces a high voltage vh (Fig. 4 e) in the secondary coil 2b, which generates a spark in the ignition plug 3 and ignites the engine. . Negative polarity voltage Vl induced in exciter coil 1
The peak value of increases as the engine speed increases, and the voltage 7
1 reaches the Zener level of the Zener diode (13) 10 as the phase progresses, so the ignition position θl advances as the engine speed increases. The characteristic of this ignition position θ1 with respect to the engine rotational speed N is shown by the curve in FIG.

In the conventional ignition device, since there is no signal control circuit 11, an ignition signal is given to the discharge control thyristor 9 by the negative voltage v3 generated following the positive voltage v2. This negative polarity voltage v3 delays the start-up 9 due to the armature reaction caused by the charging current of the capacitor 7, so the ignition position is delayed, and this delay in the ignition position is caused by an increase in the engine speed as shown by curve a in FIG. It becomes more noticeable as On the other hand, in the present invention, the ignition signal is given to the discharge control thyristor 9 at the negative polarity voltage v1 of the half cycle before the half cycle of the positive polarity voltage v2 (the half cycle for charging the ignition energy storage capacitor). Therefore, it is not affected by armature reaction, and as shown in the curve in FIG. 5, the ignition position θl is not delayed when the engine is running at high speed.

One feature of the present invention is that a current limiting resistor 21 is provided. In the above embodiment, since a large short-circuit current flows through the current-limiting resistor 21, the short-circuit current flows for a long period of time due to armature reaction.
+ <Nz <N3), the current waveforms of the exciter coil 1 are shown by the symbols N, , N2 and N3 in FIG. 6, respectively. Therefore, in a high-speed region where the rotational speed exceeds N2, the thyristor 12 is operated until the half cycle in which the negative polarity voltage Vl is generated, as shown by the broken line in FIG. 4(d).
continues to conduct, and as shown by the broken line in FIG. 4(c), the voltage applied to the Zener diode 10 becomes lower even during the period of angle θ4 to θ1 where the negative polarity voltage Vl is generated. Therefore, the ignition operation is no longer performed.

On the other hand, if the current limiting resistor 21 is provided as in the present invention,
Since the current flowing through the exciter coil when the thyristor 12 is conductive is limited, the armature reaction is reduced and the period during which the current 1b flows is shortened. Therefore, even at high speeds, the thyristor 12 enters the L-interrupted state at a position before the angle θ4 at which the negative polarity voltage v1 rises, and the ignition operation can be carried out without any trouble.

Next, consider a case where the magnet rotor 30 rotates in the opposite direction in the generator shown in FIG. In this case, first a positive voltage v3' is generated in the exciter coil 1, as shown in FIG. 3(b), and then a negative voltage vz' is generated. The positive polarity voltage v3' charges the capacitor 7 and the capacitor 14, and the charge of the capacitor 14 provides an ignition signal to the υ thyristor 12. Therefore, as soon as the negative polarity voltage v2' occurs following the positive polarity voltage v3', the thyristor 12 becomes conductive and the supply of the ignition signal to the thyristor 9 is blocked. The capacitor 14 is completely discharged while the negative polarity voltage v2' is generated, but is charged again when the positive polarity voltage v1' is generated next, and is also charged by the next positive polarity voltage v3'. Therefore, when the negative polarity voltage v2' is generated next time, the thyristor 12 becomes conductive to prevent the supply of the ignition signal to the discharge control thyristor 9. In this way, when the generator is reversed, the thyristor 9
Since no ignition signal is given to the ignition operation, no ignition operation is performed. Therefore, when the present invention is applied to a two-cycle engine, it also serves as a device for preventing reverse rotation of the engine.

In the above embodiment, the ignition energy storage capacitor 7 is provided in series with the primary coil 2a of the ignition coil,
The discharge control thyristor 9 is connected to the capacitor 7 and the primary coil 2.
Although the capacitor discharge type ignition circuit is provided in parallel to the series circuit with a, it is sufficient that the capacitor discharge type ignition circuit discharges the charge of the capacitor 7 to the primary coil 2a when the thyristor 9 is conductive. In Figure 1, capacitor 7
It is also possible to switch the positions of the thyristor 9 and the thyristor 9.

Also Dunno e diode 8 and Zener diode 10
can be omitted.

In the above embodiment, the second discharge circuit for the capacitor 14 is constructed using the transistor 18, but a thyristor may be used instead of the transistor. Also, without using transistors or thyristors, capacitor 1
The second discharge circuit can be configured only with the resistors connected in parallel to both ends of 4. (17) If the charge in the capacitor 14 can be discharged almost completely at zero speed through the resistor 15 and the r-) cathode of the thyristor 12 before the negative polarity voltage v1 rises,
This second discharge circuit can be omitted.

In some cases, the discharge time constant of the capacitor 14 may be set so that a charge remains in the capacitor 14 when the negative polarity voltage V1 rises above the set rotational speed of the engine at high speed. Since the ignition operation is no longer performed at a rotation speed higher than the set rotation speed, an over-speed prevention effect can be obtained.

Furthermore, by appropriately setting the size of the current limiting resistor 21, it is possible to prevent the ignition operation at high speeds and prevent over-speed rotation.

As described above, the present invention has the advantage that it is possible to eliminate the influence of the armature reaction of the magnet generator, thereby preventing delays in the ignition position at high speeds, and also preventing ignition operations during reverse rotation. Furthermore, in the present invention, since the current limiting resistor (18) is inserted in series in the path of the current flowing from the exciter coil through the signal control thyristor, it is possible to extend the rotation range in which the ignition operation can be performed without any trouble to the high speed range. The engine can be ignited without any problem even at high speeds.

[Brief explanation of drawings]

Fig. 1 is a connection diagram showing a circuit of an embodiment of the present invention, Fig. 2 is a front view showing an example of a magnet generator used in the invention, with some parts omitted and a part cut away, and Fig. 3 Figures (a) and (b) are voltage waveform diagrams of the generator shown in Figure 2 during normal rotation and during normal rotation, respectively;
FIG. 5 is a diagram showing the characteristics of the ignition position with respect to the rotational speed of the ignition device of the present invention and the conventional ignition device. 1... Exciter coil, 2... Ignition coil, 3...
... Spark plug, 4-6... Diode, 7... Capacitor for ignition energy storage, 9... Thyristor for discharge control, 12... Thyristor for signal control, 13...
Resistor, 14... Signal control capacitor, 16... Resistor, 17... Diode, 18... Transistor (
Semiconductor switch for reset), 19...Resistor.

Claims (1)

[Claims] The ignition coil and the first magnet, which is provided in the magnet generator that rotates in synchronization with the rotation of the internal combustion engine and has a negative polarity when the engine rotates forward,
an exciter coil that sequentially outputs a half-cycle voltage, a second half-cycle voltage of positive polarity, and a third half-cycle voltage of negative polarity; The ignition energy storage capacitor is charged to one polarity by the positive output voltage, and when the capacitor is electrically connected, the charge of the capacitor is transferred to one of the ignition coils.
A capacitor discharge type comprising: a discharge control thyristor provided to cause discharge to the next coil; and a signal supply circuit that supplies an ignition signal to the thyristor using the negative output voltage of the exciter coil at the ignition position of the engine. In an internal combustion engine ignition system, a signal control capacitor charged to one polarity by the positive output voltage of the exciter coil and the negative output voltage of the exciter coil are substantially short-circuited. a signal control thyristor provided in parallel with the exciter coil in a direction in which the anode and cathode are forward biased with an output voltage of , and a current flowing from the exciter coil through the anode and cathode of the signal control thyristor. A capacitor discharge type internal combustion engine ignition comprising: a current limiting resistor inserted in series in a passageway; and a discharge circuit for discharging the electric charge of the signal control capacitor through a dart cathode of the signal control thyristor. Device.