JPH0717816Y2 - Ignition device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a current interruption type ignition device for an internal combustion engine using a transistor switch as a switching element for current control.

[Prior Art] A conventional ignition device of this type is shown in FIG. In the figure, 1 is an ignition coil, 2 is an ignition plug attached to a cylinder of an engine (not shown) and connected to a secondary coil 1b of the ignition coil, and 3 is a collector-emitter circuit for the primary coil 1a of the ignition coil. NPN connected in parallel
The transistor switch 4 composed of the transistor T _r1 is an NPN transistor T _r2 in which the collector-emitter circuit is connected in parallel between the base and emitter of the transistor switch 3.
A semiconductor switch for cutoff control consisting of 5
Resistors for supplying a base current to T _r1 and 6 and 7 are bleeder resistors of the transistor T _r2 .

The ignition coil 1 is provided in a magneto generator attached to an internal combustion engine, and an AC voltage is induced in the primary coil 1a in synchronization with the rotation of the engine. That is, in this example, 1 of the ignition coil 1
The next coil 1a also serves as the ignition power supply coil.

In this type of ignition device, the ignition operation is performed by using the voltage of one half polarity of the alternating voltage induced in the ignition power supply coil. In this specification, of the two half cycles of the AC voltage induced in the ignition power supply coil (primary coil), the half cycle in which the ignition operation is performed is defined as the positive half cycle.

If the primary coil 1a positive voltage half cycle of the arrow direction of FIG. 6 is induced, the base current flows through the transistor T _r1 becomes conductive the transistor T _r1, the collector emitter of the transistor T _r1 from the primary coil 1a Short-circuit current flows through the gap. This short-circuit current increases and the transistor T
_When the collector-emitter voltage of _r1 reaches a predetermined value, the transistor T _r2 becomes conductive and cuts off the transistor T _r1 . As a result, the current flowing through the primary coil 1a is cut off, so that a high voltage is induced in the primary coil 1a, and this voltage is further boosted to obtain a high voltage for ignition in the secondary coil 1b. Since this high voltage is applied to the spark plug 2, a spark is generated in the spark plug 2 and the engine is ignited.

[Problems to be Solved by the Invention] In the above ignition device, the ignition operation is always performed when the ignition power supply coil generates a voltage of a positive half cycle. Therefore, when the magneto-generator is configured with multiple poles and a positive half cycle voltage is generated multiple times per revolution of the engine,
Ignition operation is performed each time a voltage of each positive half cycle is generated, and if the number of positive half cycle voltages generated from the ignition power supply coil does not match the required number of ignitions, a dead fire occurs. Will fly.

Therefore, by providing another signal source for triggering the interruption control semiconductor switch 3 and giving a trigger signal from the other signal source to the interruption control semiconductor switch, it is necessary for one revolution of the engine. There is one in which the ignition operation is performed only a number of times.

However, even with such a configuration, the ignition power supply coil is short-circuited by the transistor switch every time a positive half-cycle voltage is generated.Therefore, when a multipolar generator is used, There has been a problem that the short-circuit current flows for a long time and heat generation increases.

An object of the present invention is to provide an ignition device for an internal combustion engine which suppresses heat generation of an ignition power supply coil and can perform an ignition operation a necessary number of times per rotation.

[Means for Solving the Problems] The present invention is directed to an ignition power supply coil that outputs an alternating voltage of a plurality of cycles per rotation in synchronization with the rotation of an internal combustion engine, and the ignition power supply coil connected in parallel to the ignition power supply coil. A transistor switch that is turned on when a base current is given from the ignition power coil when the power coil outputs a voltage of a positive half cycle, and a cutoff that is turned on to turn off the transistor switch when triggered. Internal combustion engine having a control semiconductor switch and a signal source for giving an ignition timing determination trigger signal to the cutoff control semiconductor switch at an ignition timing set within a specific positive half cycle of the output of the ignition power supply coil The present invention relates to an ignition device for a vehicle.

In the present invention, a base current supply control semiconductor switch is inserted in the base current supply path of the transistor switch. In addition to generating the ignition timing determination trigger signal, the signal source is used to determine the energization start timing at the energization start timing set between the ignition timing and the start timing of the specific positive half cycle of the output of the ignition power supply coil. Generate a trigger signal,
The trigger signal is applied to the base current supply control semiconductor switch.

[Operation] As described above, when a trigger signal is applied to the base current supply control semiconductor switch to make the transistor switch conductive only in the positive half cycle in which the ignition operation is performed, the positive operation in which the ignition operation is not performed is performed. In the half cycle, since the ignition power supply coil is not short-circuited, it is possible to suppress the heat generation of the ignition power supply coil by minimizing the time during which the short-circuit current flows through the ignition power supply coil.

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

FIG. 1 shows an embodiment of the present invention, in which 1 is an ignition coil, 2 is an ignition plug attached to a cylinder of an engine and connected to a secondary coil 1b of the ignition coil,
One ends of the primary coil 1a and the secondary coil 1b of the ignition coil 1 are grounded. The ignition coil 1 is provided in a magnet generator attached to an internal combustion engine, and a primary coil 1a of the ignition coil also serves as an ignition power supply coil. _{Reference numeral} 3 denotes a transistor switch composed of an NPN transistor T _{r1 in} which the collector-emitter circuit of the transistor T _r1 is connected in parallel to the primary coil 1a. One end of the resistor 10 is connected to the base of the transistor T _r1 and the thyristor T _h1 which constitutes the cut-off control semiconductor switch 4 is connected between the other end of the resistor 10 and the ground.
Is connected with its cathode facing the ground side. resistance
A thyristor forming a base current supply control semiconductor switch 11 between the other end of 10 and the non-grounded side terminal of the primary coil 1a.
T _h2 is connected with its anode facing the primary coil. The gates of the thyristors T _h1 and T _h2 are connected to the cathodes of the diodes 12 and 13, respectively, and the signal coil 14 forming a signal source is connected between the anodes of these diodes. Diodes 15 and 16 are connected between the anode of the diode 12 and the ground and between the anode of the diode 13 and the ground, respectively, with their anodes facing the ground side.

FIG. 3 shows an example of a magnet generator in which the ignition coil 1 and the signal coil 14 are provided. In FIG. 3, 20 is a cup-shaped iron flywheel 21 having four inner circumferences.
The magnet rotor is provided with permanent magnets 22, 22, ..., The magnets 22, 22, ... Are magnetized so that different magnetic poles are alternately arranged in the circumferential direction of the flywheel. Reference numeral 23 is a stator arranged inside the magnet rotor 20, and this stator is formed by winding the ignition coil 1 around an armature core 23a. Inside the magnet rotor, other stators provided with a magneto coil for driving other loads such as headlamps are arranged, but these stators are not shown.

An inductor 24 is projectingly provided on the outer periphery of the flywheel 21, and the magnetic pole portion of the signal emitting electron 25 is opposed to the inductor 24.
The signal emitting electron 25 is an iron core having a magnetic pole portion facing the inductor 24.
A signal coil 14 is wound around the iron core 25, which includes a magnet (not shown) for flowing a magnetic flux to the iron core 25a.

In the above ignition device, when the engine rotates, an AC voltage is induced in the primary coil 1a for two cycles per rotation as shown in FIG. 2 (A). In the present embodiment, the ignition operation is performed by the voltage V _p2 generated later out of the voltages V _p1 and V _p2 of the positive half cycle generated twice per rotation. The signal coil 14 induces a positive polarity signal V _sp and a negative polarity positive voltage V _sn each time the magnetic pole of the signal generator 25 faces the inductor 24. In this example, as shown in FIG. 2 (B). As described above, the signal V _sp exceeds the trigger level of the thyristor T _h2 immediately after the voltage V _p2 of the positive half cycle used to perform the ignition operation rises, and the voltage of the negative polarity is almost negative at the position where the voltage V _p2 reaches the peak. The signal V _sn is set to exceed the trigger level of thyristor T _h1 .

When the primary coil 1a generates the voltage V _p1 , the thyristor T _h2 is not supplied with a trigger signal, so that the thyristor is not conductive and the base current is not supplied to the transistor T _r1 . Therefore the transistor T _r1 does not conduct, the ignition operation is not performed.

When the primary coil 1a generates a positive half-cycle voltage V _p2 , the signal coil 14 generates a positive polarity signal V _sp .
Signal coil 14 → diode 13 → thyristor T _h2 gate cathode → transistor T _r1 base emitter → diode 15 → signal coil 14
11 becomes conductive, and a base current flows through the transistor T _r1 .
Thus the transistor T _r1 is turned on, the short-circuit current from the primary coil 1a through the collector-emitter of the transistor T _r1 flows. Then the signal coil at the ignition position of the internal combustion engine
When 14 generates a signal V _{sn of} negative polarity, current flows in the route of signal coil 14 → diode 12 → thyristor gate cathode of thyristor T _h1 → diode 16 → signal coil 14, causing thyristor
T _h1 becomes conductive. Thus the supply of the base current to the transistor T _r1 is prevented, the transistor T _r1 is the cut-off state, the current flowing through the primary coil 1a is cut off. Therefore, a high voltage is induced in the primary coil 1a in the direction in which the current that has been flowing until now continues to flow, and this voltage is further boosted to obtain a high voltage for ignition in the secondary coil 1b. Since this high voltage is applied to the spark plug 2, a spark is generated in the spark plug 2 and the engine is ignited.

As described above, in the present invention, the base current supply control semiconductor switch 11 is provided in the middle of the base current supply circuit of the transistor switch provided in parallel with the ignition power supply coil, and in the half cycle in which the ignition operation is performed. only, since as the trigger signal is applied to the base current supply control semiconductor switch, transistor T _r1 is not conducting when the voltage V _p1 of not used for the ignition operation the positive half cycle is generated, the ignition power supply coil Does not flow current. Therefore, it is possible to prevent useless short-circuit current from flowing through the ignition power supply coil, and suppress heat generation of the ignition power supply coil.

FIG. 4 shows another embodiment of the present invention, in which the ignition coil 1 is provided outside the magnet generator.
The exciter coil 30 provided in the magnet generator is used as an ignition power supply coil. The exciter coil 30 is one end is grounded, both ends of the exciter coil 30 collector-emitter circuit of the transistor T _r1 is connected in parallel to the ground side of the emitter. Ignition coil 1
One end of the secondary coil 1a is connected to the non-grounded side terminal of the exciter coil 30, the other end of the primary coil 1a is connected to one end of the resistor 10 through the thyristor T _{h2, and} the other end of the resistor 10 is connected to the base of the transistor T _r1 . It is connected. The thyristor T _h1 is connected between one end of the resistor 10 and the ground, and the cathodes of the diodes 12 and 13 are connected to the gates of the thyristor T _h1 and the thyristor T _h2 , respectively. A signal coil 14 is connected between the anodes of the diodes 12 and 13, and diodes 15 and 16 with their anodes facing the ground side are connected between the anode of the diode 12 and the ground and between the anode of the diode 13 and the ground, respectively.

In this example, the exciter coil 30 induces an AC voltage of 2 cycles per revolution of the engine, as shown in FIG. Of the positive half-cycle voltages V _p1 and V _p2 generated by the exciter coil during one revolution of the engine, the voltage V generated first
Ignition shall be performed by _p1 . In this case, the signal coil 14 is at the position immediately after the rise of the voltage V _{p1 and} the voltage V _p1.
Signals V _sp and V _sn are generated near the peak position of _p1 , respectively.

In this igniter, when the exciter coil 30 generates a positive half cycle voltage V _p1 in the direction of the arrow shown, the signal coil 14 subsequently causes the thyristor T _h2 through the diode 13.
Give a trigger signal to. Thus by conducting thyristor T _h2 provide the base current to the transistor T _r1, thereby turning on the transistor T _r1. Signal coil 1 for engine ignition timing
When 4 generates the signal V _sn , the thyristor T _h1 becomes conductive and turns off the transistor T _r1 . As a result, the current flowing through the exciter coil 30 is cut off, so that a high voltage is induced in the exciter coil. This voltage is boosted by the ignition coil 1 to obtain a high voltage in the secondary coil 1b, and the ignition operation is performed.

Exciter coil 30 has a second positive half cycle voltage V
_{When p2} is generated, the signal coil 14 does not generate a signal, so the thyristor T _h2 does not conduct. Therefore the transistor T _r1 does not conduct, the ignition operation is not performed.

In the above-mentioned embodiment, the ignition operation is performed once per one rotation, but the signal source (the signal coil 14 in the above example) outputs the signal V
_{By configuring sp} and V _sn to be generated a plurality of times at different positions, it is possible to perform a plurality of ignition operations per rotation.

In the above-mentioned embodiment, the semiconductor switch for controlling the base current supply is constituted by the thyristor.However, when this switch is triggered in the state where the positive half cycle output voltage of the ignition power supply coil is applied, the ignition operation is performed. The switch is not limited to the thyristor as long as the switch has a function of self-holding until it is released.

The signal source is not necessarily limited to the signal coil shown in the above example, and the start timing and ignition timing of a specific positive half cycle (positive half cycle for performing the ignition operation) of the output of the ignition power coil. Any element may be used as long as it generates the energization start timing determination trigger signal at the energization start timing set during the period and the ignition timing determination signal is generated at the ignition timing.

[Advantage of the Invention] As described above, according to the present invention, the base current supply control semiconductor switch is inserted in the base current supply passage of the transistor switch to perform the base operation only in the positive half cycle in which the ignition operation is performed. Since the transistor switch is made conductive only in the positive half cycle in which the ignition operation is performed by giving the trigger signal to the current supply control semiconductor switch, the time to flow the short-circuit current to the ignition power supply coil must be minimized. It is possible to suppress the heat generation of the ignition power supply coil.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a voltage waveform diagram of an essential part of FIG. 1, and FIG. 3 is a schematic diagram showing a configuration example of a magnet generator used in the embodiment. FIG. 4 is a circuit diagram showing another embodiment of the present invention, FIG. 5 is a voltage waveform diagram of an essential part of FIG. 4, and FIG. 6 is a circuit diagram showing a configuration of a conventional ignition device. . 1 ... Ignition coil, 1a ... Primary coil, 1b ... Secondary coil, 3 ... Transistor switch, 4 ... Breaking control semiconductor switch, 11 ... Base current supply control semiconductor switch, 14 ... Signal Coil, 30 ... Exciter coil.

Claims (1)

[Scope of utility model registration request] 1. An ignition power supply coil that outputs an AC voltage of a plurality of cycles per rotation in synchronization with the rotation of an internal combustion engine, and a positive half cycle in which the ignition power supply coil is connected in parallel with the ignition power supply coil and is positive. A transistor switch that is turned on when a base current is applied from the ignition power supply coil when the voltage is output, and a cutoff control semiconductor switch that is turned on to turn off the transistor switch when triggered. An ignition device for an internal combustion engine, comprising: a signal source that gives an ignition timing determination trigger signal to the cutoff control semiconductor switch at an ignition timing set within a specific positive half cycle of the output of the ignition power supply coil. The base current supply control semiconductor switch is inserted in the middle of the base current supply path of the transistor switch, and the signal source is In addition to generating the ignition timing determination trigger signal, the energization start timing determination trigger signal is set at the energization start timing set between the ignition timing and the start timing of the specific positive half cycle of the output of the ignition power supply coil. And an ignition device for an internal combustion engine, wherein the energization start timing determination trigger signal is given to the base current supply control semiconductor switch.