JPS5836187B2 - Nainenkikanyoutenkasouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a magneto generator driven by an internal combustion engine, the generator winding of which is connected to one of the ignition coils.
The secondary winding of the ignition coil is connected to at least one spark plug, and the primary winding of the ignition coil is connected in series with the switching section of the controllable semiconductor element. In this case, a Zener diode or a cyrisk bridges the series connection between the primary winding and the semiconductor element. The present invention relates to an ignition device for an internal combustion engine.

In magneto generators that supply power to other loads in addition to high-power ignition devices, the ignition coil of the ignition device is installed outside the magneto generator in order to effectively use the energy from the magneto generator. improves power delivery to other loads.

Devices of this type are used, for example, on snowmobiles. In this type of device, the primary current of the ignition coil must be changed rapidly at the ignition timing to ensure that a sufficiently large voltage is induced on the secondary side of the ignition coil and an ignition spark is generated. .

For this purpose, it is known to connect the ignition armature winding of a magneto generator to the primary winding of an ignition coil via a thyratron.

The conduction of the thyratron is controlled by a pulse generator at the ignition timing.

As a result, the primary current begins to flow rapidly, inducing a high voltage in the secondary winding of the ignition coil, which is necessary to generate an ignition spark in the ignition plug.

However, this type of ignition system is not suitable for use in new internal combustion engines.

This is because in this type of ignition device, the inductance of the ignition coil is insufficient and therefore the change in current caused by the closure of the primary circuit is also limited, making it impossible to obtain a sufficiently large ignition voltage.

It is known to interrupt the alternating current in the primary circuit by means of a mechanical interrupter when it reaches its peak, thereby obtaining a sudden change in current.

L-bar mechanical interrupters are subject to wear and tear and therefore require periodic maintenance or replacement.

If an electronic switch element is used and conduction of the switch element is controlled at the ignition timing, it can be used in place of a circuit breaker, but on the other hand, there is a risk that the electronic switch element may be destroyed by a large cut-off voltage.

This type of cut-off voltage is generated by combining the voltage that occurs in the generator winding of the generator and the voltage that occurs in the primary winding of the ignition coil when the primary circuit is opened.

The basic object of the present invention is to combine the advantages of a circuit breaker for disconnecting the primary circuit of an ignition system with the advantages of a maintenance-free electronic switch element, while protecting the electronic switch element against excessive cut-off voltages. The purpose is to provide an ignition device.

According to the present invention, this problem is solved as follows.

That is, in the ignition device of the type described at the beginning, a thyristor and a series connection body of a Zener diode and a resistor are connected in parallel with the generator winding, and in this case, the control electrode of the thyristor is connected to the anode of the Zener diode. The cathode of the Zener diode is directly connected to the anode of the Cyrisk, and when the current in the primary winding is cut off, the Zener diode ignites the Cyrisk with a correspondingly high Zener voltage.

The damping element is then connected, for example, in parallel to the generator winding.

According to an embodiment of the present invention, a limit value is provided on the damping element and the damping element is connected such that it responds when the potential at the terminals of the ungrounded generator winding exceeds a predetermined positive potential. .

In this way, when the primary current is cut off, the induced voltage in the generator winding is limited to a relatively small value, and at the same time, the induced voltage generated in the ignition coil due to the cutoff of the primary current (therefore, ignition energy) is not affected.

It is only necessary that the induced voltage in the primary winding of the ignition coil be interrupted by the electronic switching element.

Next, the present invention will be explained in detail with reference to the drawings with reference to embodiments.

FIG. 1 shows a coil ignition system for a single cylinder internal combustion engine.

The circuit of FIG. 1 is powered by a magneto generator 10. The circuit of FIG.

The magneto generator 10 includes a magnetic pole wheel 11 rotated by an internal combustion engine (not shown), a plurality of permanent magnets 12, an ignition armature 13, and a generator winding 14.

One end 14b of the generator winding 14 is grounded.

The other end 14a of the generator winding 14 is connected via a wire 15 to one end of the primary winding 16a of the ignition coil 16.

The ignition coil 16 is provided outside the magneto generator 10.

A secondary winding 16b of the ignition coil 16 is connected to a spark plug 18 via an ignition cable 17.

One end of the spark plug 18 and one end of the two missing windings 16b of the ignition coil 16 are grounded.

One end of the primary winding 16a of the ignition coil 16 is connected to a control device.

The control device has an ignition transistor 20.

The switching section of the ignition transistor 20 is connected as an electronic semiconductor component to the primary circuit of the ignition coil 16.

The primary winding 16a is connected via a diode 21 to the collector of an npn ignition transistor 20.

The emitter of transistor 20 is grounded.

The anode of the diode 21 is connected to the base of the ignition transistor 20 via a resistor 22.

A switching section of a control transistor 23 is connected in parallel to the control section (base-emitter) of the ignition transistor 20.

The base of the control transistor 23 is a Zener diode 31
and is connected to the anode of the diode 21 via the resistor 24.

The base of transistor 23 is further connected via a diode 25 to a secondary winding 26 of a pulse generator 27 .

A resistor 28 is connected in parallel between the emitter and base of the control transistor 23.

One end of the secondary winding 26 of the pulse generator 27 and the emitter of the transistor 23 are grounded.

The pulse generator 27 generates a pulse at the ignition timing by a source piece 32 rotating in the direction of the arrow.

The magnetically conductive piece 32 and the magnetic pole wheel 11 of the magneto generator 10 are driven by an internal combustion engine.

A Zener diode 29 is connected in parallel with the generator winding 14, i.e. its cathode is connected to the generator winding 1.
It is connected so as to be coupled to the terminal 14a on the other side of No. 4, which is not on the ground side.

The anode of the Zener diode 29 is connected to ground via a resistor 30 connected in series.

A thyristor 41 is connected in parallel with this series connection body.

In this case, the control electrode 41a of the SIRISK is connected to the anode side of the Zener diode 29.

Generally, the cathode of the Zener diode 29 is connected to the anode side of the thyristor 41.

This connection constitutes a damping element 40 that damps the generator voltage during the ignition process.

The limit value of the Zener diode 29 is fixed to, for example, 10.

This value is selected such that this limit voltage is not exceeded when a load is connected to the generator winding 14.

Damping element 40 therefore does not react when ignition transistor 20 conducts.

Next, the operation of the ignition device shown in FIG. 1 will be explained.

During operation of the internal combustion engine, rotation of the magnetic pole wheel 11 induces an alternating current voltage in the generator winding 14 .

When the first positive half wave of the induced voltage in the generator winding 14 occurs and the voltage value of the induced voltage exceeds the cutoff voltage of the diode 21,
The induced voltage is applied to the base of the ignition transistor 20 via the resistor 22.

Since the emitter of the ignition transistor 20 is grounded, a base current flows due to the induced voltage.

The conduction of the transistor 20 is controlled by this base current.

As a result, the primary circuit of the ignition coil 16 is connected to the generator winding 14,
It is closed through the primary winding 16a of the ignition coil 16, the diode 21, and the emitter-collector of the ignition transistor 20.

The primary current flows through the primary circuit.

Only the voltage drop necessary to keep the ignition transistor 20 conductive then occurs between the diode 21 and the emitter-collector of the ignition transistor 20.

As a result, what is the generator winding 14? It will be short-circuited.

Therefore, a large current flows due to the induced voltage in the generator winding 14, and a strong magnetic field is generated in the ignition coil 16 by this primary current.

On the other hand, a control pulse is generated by the magnetic pulse generator 27 at the ignition timing.

This control pulse is applied to the base of control transistor 23 via diode 25.

As a result, the control transistor 23 is controlled to be conductive.

The emitter and base of the ignition transistor 20 are then bridged, and the ignition transistor 20 is immediately rendered non-conducting.

Therefore, since the primary current is interrupted in this case, the magnetic flux changes rapidly in the ignition armature 13 and the ignition coil 16 of the magneto generator 10.

This change in magnetic flux causes the generator winding 14 and the primary winding 1 to
A large voltage is induced at 6a.

As soon as the voltage of the generator winding 14 exceeds the limit voltage of the Zener diode 29, the Zener diode is made conductive and the thyristor 41 is fired.

The silisk therefore bridges the generator winding 14.

Therefore, the current induced by the generator winding 14 flows through the thyristor 41.

Cyrisk damps the generator voltage U2 to almost zero.

Said process does not affect the primary and secondary voltages induced in the ignition coil 16.

This is because the control transistor 23 is further controlled to be conductive via the resistor 24 and the Zener diode 31, and the ignition transistor 20 is therefore kept non-conductive.

An ignition spark is generated in the ignition plug 18 by the high voltage pulse generated in the secondary winding 16b of the ignition coil 16.

This type of ignition system allows the use of high-power ignition coils.

This means that the large primary voltage U, no longer ignites the transistor 2.
This is because, since the output voltage U2 of the magneto generator 11 is limited to a small value, the cutoff voltage U5 occurring between the collector and emitter of the ignition transistor 20 is significantly reduced.

The voltage indicated by the arrow in FIG. Thyristor 41 when passing the zero point
is cut off, and on the other hand the voltage of the Zener diode in the control device 19 also falls below the limit value voltage.

Therefore, the control transistor 23 is also switched to the cut-off state again.

The next negative voltage half-wave of the generator winding 14 is not connected to the load, because the next negative half-wave of the induced voltage in the generator winding 14 is not controlled.

This is because negative voltage half-waves are not harmful to the reverse biased ignition transistor 20.

[Brief explanation of the drawing]

The figures serve to explain the present invention, and FIG. 1 shows a block diagram of an embodiment of the ignition device of the present invention. 11... Magneto generator, 14... Generator winding, 16... Ignition coil, 18...
...Spark plug, 19...Control device, 20...
...Ignition transistor, 23...Control transistor, 27...Pulse generator.

Claims (1)

[Claims] 1 It has a magneto generator driven by an internal combustion engine,
A generator winding of the magneto generator is connected to a primary winding of an ignition coil, and a secondary winding of the ignition coil is connected to at least one
The primary winding of the ignition coil is connected in series with the switching section of a controllable semiconductor element, and the semiconductor element is controlled by the control device to control the current of the primary winding at the ignition timing. In an ignition system for an internal combustion engine in which a zener diode or a thyristor bridges a series connection between a primary winding and a semiconductor element, a thyristor 41 is connected in parallel with the generator winding 14. and,
A series connection body of the Zener diode 29 and the resistor 30 is connected, and in this case, the control electrode 41 of the thyristor 41
a is connected to the anode of the Zener diode 29, and the cathode of the Zener diode is directly connected to the anode of the thyristor 41. When the current in the primary winding is cut off, the Zener diode 29 is connected to the thyristor 41 by a correspondingly high Zener voltage. An ignition device for an internal combustion engine, characterized in that it ignites.