JPS5938430B2 - Ignition system for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention cooperates with a magnet system rotationally driven by an internal combustion engine for the generation of ignition energy, a current circuit is connected to the coils of said magnet system, and a controllable electronic A switching section of a semiconductor circuit element is provided, said semiconductor circuit element simultaneously forming a primary current circuit of an ignition coil, the secondary coil of which is connected via an ignition cable to at least one spark plug, in which case the semiconductor circuit element The present invention relates to an ignition device for an internal combustion engine, in which a control electrode is connected to a control current circuit, and the control current circuit controls switching of a conductive semiconductor circuit element to a cutoff state by a control signal from a control device at the time of ignition.

In the case of so-called coil ignition systems, the primary current circuit connected before the ignition point of the ignition system is opened by a semiconductor circuit element, for example an ignition transistor.

At that time, the magnetic field of the ignition coil formed by the primary current is extinguished, and a high voltage pulse is induced in the secondary coil.
This pulse causes the spark plug to produce an ignition spark.

Subsequently, the primary current circuit must be closed again in order to generate the ignition spark.

In the case of a battery-powered ignition system, the control voltage required for switching the ignition transistor can be tapped off from the terminals of the battery.

In the case of so-called magneto igniters, the voltage at the terminals of the ignition inductor may be very low in the case of a short-circuited primary current circuit to keep the ignition transistor fully conductive, but this condition is It is necessary for the formation of a strong magnetic field in the ignition inductor.

In known transistor-controlled magneto ignition devices, the ignition transistor is connected in series with a resistor in the primary current circuit.

When a positive voltage half-wave occurs across the ignition inductor, the ignition transistor is switched into conduction by means of the voltage developed across this resistor or remains conductive until the ignition point.

At the point of ignition, the base-emitter section of the ignition transistor is bridged, and in this way the ignition transistor is switched off.

This type of solution has the following disadvantage: the resistor only causes the current limitation and thus the required generation of the magnetic field in the ignition inductor during the positive voltage half-wave. This undesirably loads the primary current circuit.

As a result, when the primary current circuit is interrupted, the high voltage generated by the ignition transistor in the secondary coil of the ignition inductor is strongly reduced by the ignition transistor.

The object of the invention is to design a transistor-controlled magneto ignition device in such a way that the increase in the primary current to be interrupted at the time of ignition does not depend on the control element of the ignition transistor in the primary current circuit.

In order to solve this problem, the invention provides an ignition inductor which cooperates with a magnet system rotationally driven by an internal combustion engine for the generation of ignition energy, and a current circuit is connected to the coil of the ignition inductor, The circuit is provided with a switching section of a controllable electronic semiconductor circuit element, which semiconductor circuit element simultaneously forms the primary current circuit of the ignition coil and connects the secondary coil to at least one spark plug via an ignition cable. connecting a control electrode of the semiconductor circuit element to a control current circuit, the control current circuit having a control transistor and a pulse generator, and connecting the collector-emitter section of the control transistor to the control section of the semiconductor circuit element. are connected in parallel to each other, and the pulse generator is configured to send out a pulse for controlling the conduction of the control transistor at the time of ignition, and therefore controlling the switching of the semiconductor circuit element from a conductive state to a cut-off state. In the ignition system for internal combustion engines,
The base of the control transistor is connected directly to the terminals of the primary coil via a tap of a voltage divider, in which case the voltage pulse formed in the primary coil during the ignition process is connected to the base of the control transistor by the terminal of the primary coil. The connection is such that it acts directly via the pressure vessel.

In this ignition system, the negative voltage half-wave of the magneto igniter charges a capacitor which controls the ignition transistor into conduction during each subsequent positive voltage half-wave, so that the primary current circuit is connected to the ignition transistor. A strong primary current flows which is directly short-circuited by and is no longer influenced by the resistance in the primary current circuit for the generation of the control voltage for the ignition transistor.

Next, the present invention will be described in detail using illustrated embodiments.

The ignition system for a single-cylinder internal combustion engine shown in FIG. forming a coil.

An ignition inductor 11 arranged in the housing of the internal combustion engine cooperates with a magnet system 13 having a permanent magnet 13a which is driven one rotation by the internal combustion engine.

Ignition inductor 110 secondary coil 12a is connected to ignition cable 14
is connected to the ignition plug 15 via the ignition inductor 1.
The 101st coil 12b is connected to a primary current circuit in which the collector-emitter section of the ignition transistor 16 is arranged.

The ignition transistor 16 is designed as an NPN output transistor, the emitter wire of which is connected to ground as well as the end of the ignition inductor 110 primary coil 12b.

The primary coil 12b is bridged by a capacitor 17 and a diode 18 connected in series with this capacitor, which diode 18 is polarized in the opposite conduction direction to the collector-emitter of the ignition transistor 16.

The connection point 19 between the capacitor 17 and the diode 18 is connected to the ignition transistor 160 via a high resistance resistor 20.
connected to the base.

Another control circuit is connected to the base of ignition transistor 160, and this control circuit includes control transistor 2.
1 is provided, and its collector-emitter is connected in parallel between the base and emitter of the ignition transistor 16.

A magnetic pulse transmitter 22 is provided in parallel between the base and emitter of the control transistor 21 for activation of the ignition process.

Furthermore, the base of the control transistor 210 is the resistor 2 of the voltage divider.
3 to ground, and the ignition inductor 110 not connected to ground via a voltage divider resistor 24 to the other end of the primary coil 12b.

Furthermore, the primary coil 12b is bridged with a damping element 25 for the negative voltage half-wave in the primary current circuit.

The damping element 25 has a diode 26 connected in series with a Zener diode 27, which diode 26 is polarized in the opposite direction to the collector-emitter of the ignition transistor 16.

The Zener diode 27 is polarized in such a way that it bridges the primary coil 12b of the ignition inductor 11 via the diode 26 when the Zener voltage is reached, thus eliminating the negative voltage half-wave in the primary current circuit. limit the height of

To ensure that the ignition transistor 16 is not loaded during the negative voltage half-wave, a diode 28 is provided in the primary current circuit, which diode 28 is polarized in the forward direction for the positive voltage half-wave.

Next, the operation of this ignition system will be explained in detail using the current characteristic curve and voltage characteristic curve shown in FIG.

On the axis ωt1, the course of the primary voltage U is shown by a broken line, and 1
The course of the next current ■ is shown by a solid line.

On the axis ωt2, the voltage Ub at the base of the ignition transistor 16 is shown as a broken line, the base current of the ignition transistor 16 is shown as a solid line, and the capacitor voltage U at the capacitor 17 is shown.

is shown by a dotted line.

During operation of the internal combustion engine, when the permanent magnet 13a of the magneto system 13 passes the ignition inductor 11 of the magneto igniter, a negative voltage half-wave is generated in the ignition inductor 110 primary coil 12b.

Since the Zener diode 27 bridges the primary coil 12b via the diode 26 when the Zener voltage reaches the Zener voltage, the negative voltage half-wave is limited to the Zener voltage of the Zener diode 270.

Capacitor 17 is charged via diode 18 to a negative voltage half wave limited by Zener diode 27.

Capacitor voltage U at node 19 of the circuit of FIG.

The positive potential of ignition transistor 160 is passed through resistor 20 to
Reach the base.

At the end of the negative voltage half-wave, the capacitor voltage Uo is equal to the base voltage Ub between the base and emitter of the ignition transistor 160.
It acts as.

In the case of a positive half-wave in the next ignition inductor 110 primary coil 12b, this half-wave is superimposed on the capacitor voltage U,
As a result, the base voltage Ub increases.

This base voltage Ub increases the base current ■b, which controls the ignition transistor 6 into a fully conductive state, so that the primary current circuit of the magneto igniter is actually short-circuited.

The primary current ■ increases to its maximum value, with the ignition inductor 1
A strong magnetic field is created at 1.

At the ignition point Zz, a voltage pulse is generated in the magnetic pulse generator 22, which pulse is activated by the control transistor 210.
raising the base to a positive potential and thus control transistor 2
1 to conductive state.

As a result, the base-emitter section of the ignition transistor 16 is short-circuited and the base voltage Ub disappears.

The base current b is therefore cut off and the capacitor γ is discharged via the resistor 20 and the collector-emitter section of the control transistor 21.

By interrupting the base current, the ignition transistor 6 is instantaneously interrupted.

The primary current is thereby interrupted.

The magnetic field of the ignition inductor 11 disappears, at which time the secondary coil 12
A high voltage pulse is induced in spark plug 1.
5 to produce an ignition spark.

During this process, the ignition inductor 110 primary coil 12b
Since a voltage is also induced in the capacitor, it is necessary to ensure that the control transistor 21 is maintained in a conductive state.

This and the rapid switching of the control transistor 21 is achieved by a voltage divider 23.24, which
4 transmits the increase in the primary voltage to the base of the control transistor 210 and thus keeps the control transistor 21 conductive even when the pulse oscillator 220 control pulses are almost attenuated.

Only at the end of the positive half-wave of the primary voltage Up, the control transistor 21 reaches a new cut-off range by coupling its base to the emitter via a resistor 23.

Next, the capacitor 7 is newly charged by the negative voltage half wave in the primary coil 12b.

The ignition process and the charging of the capacitor 17 are repeated with each rotation of the magnet system 13.

The invention is not limited to the illustrated embodiment, but the individual components of the circuit arrangement can also be designed differently.

The control voltage for the semiconductor circuit elements is determined by a series connection of the primary voltage and the precharged capacitor voltage to such an extent that even at low rotational speeds of the internal combustion engine or of the magnet system 10, a perfect switching control of the semiconductor circuit elements is achieved. By increasing the voltage, the semiconductor circuit components are completely switched into conduction over the entire rotational speed range when a positive voltage half-wave occurs in the primary current circuit.

Instead of the ignition transistor 16, the semiconductor circuit element can also be configured as a double transistor in a known Darlington connection.

Furthermore, the capacitor 17, the diode 18, and the damping circuit 25 can also bridge only the primary coil 12b01 portion of the ignition inductor 110.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic circuit diagram of an ignition device having a magneto igniter and an ignition transistor in a primary current circuit that is controlled to be conductive by the voltage of a capacitor, and is provided for an embodiment of the present invention. 2 is a diagram showing the course of current and voltage in the control current circuit and primary current circuit of the ignition device according to FIG. 1; FIG. 10... Magneto igniter, 11... Ignition inductor, 13... Magnet system, 16...
Ignition transistor, 22...Pulse transmitter, 2
5... Attenuation circuit, ■. ...Primary current, U ...Primary voltage, Z
・・・・・・Point p Zp Fire waiting time U ・・・・・・Capacitor voltage, Ub...
...Base pressure, ■b...Base current.

Claims (1)

[Claims] 1. An electronic semiconductor circuit element comprising an ignition inductor cooperating with a magnet system rotationally driven by an internal combustion engine for the generation of ignition energy and having a current circuit connected to the coil of the ignition inductor and controllable to this circuit. a switching section is provided, said semiconductor circuit element simultaneously forming a primary current circuit of an ignition coil, the secondary coil of which is connected via an ignition cable to at least one spark plug, the control of the semiconductor circuit element being the electrode is connected to a control current circuit, the control current circuit having a control transistor and a pulse generator, the collector emitter section of the control transistor being connected in parallel to the control section of the semiconductor circuit element; In an ignition device for an internal combustion engine, the ignition device for an internal combustion engine is configured to send out a pulse for conducting conduction control of a control transistor at the time of ignition, and thus controlling switching of a semiconductor circuit element from a conductive state to a cutoff state. 210 base is connected directly to the terminals of the primary coil 12b via a voltage divider 23, 240 tap, in which case the voltage pulse formed in the primary coil 12b during the ignition process is applied to the control transistor 210 base. Ignition system for an internal combustion engine, characterized in that the connection is configured in direct working connection via a voltage divider 23,24.