EP0181961A1 - Impulse oscillator ignition system for an internal-combustion engine - Google Patents

Abstract

1. Ignition system for an internal combustion engine with a capacitor (7) and an ignition coil, which comprises a primary winding (5) connected to ignition current switching unit (35) and a secondary winding (22) connected to the primary winding (5) in an auto-transformer series circuit, characterized in that to provide an impulse oscillator the capacitor (7) is connected to the secondary winding on its high voltage side and is connected in parallel to the series circuit of the primary winding (5) and the secondary winding (22).

Description

Technical field

The invention relates to an ignition device for internal combustion engines and other work machines excited by spark ignition with an energy source having an ignition coil or ignition transformer.

State of the art

It is known that capacitors are advantageously used in parallel with the ignition sparks and arcing paths to ground in order to improve the ignition. (Fig. 1 E.P. No. 0018622) The circuit has the disadvantage of an excessively slow voltage rise. This is due to the impedance of the long current path, because it is difficult to carry a high-frequency current signal over a more branched casting (engine block). In particular, in the known designs the charging and discharging process is carried out via a current path or series resonant circuit.

Presentation of the invention

According to the invention, this disadvantage is eliminated in that the ignition coil or ignition transformer is replaced by a pulse oscillator ignition. In this way it is understood that (according to Figure 1) parallel to A capacitor is arranged on the primary and secondary side. In this circuit, charging and discharging takes place via separate cable routing, with the charging current of the capacitor being fed back and inducing a much higher voltage across the secondary side via the primary side. In contrast to the previous designs, a correspondingly dimensioned attenuator is also arranged in the circuit according to the invention, which allows the ignition current to be extended in favor of time. The capacitor according to the invention does not directly bridge the spark gap, but the circuit closes via the primary electrolytic capacitor of the ignition coil or via the vehicle electrical system (battery).

Based on our previous tests and measurements, it has become possible to ignite extremely lean fuel-air mixtures perfectly. The pollutants in the exhaust gas are thus reduced as much as possible, and the engines can be operated without misfiring in the lean area.

According to the invention this is achieved in that the primary side of the ignition coil is acted upon by the charging current of the capacitor lying in parallel to the primary and secondary sides with a negative current potential which accelerates the magnetic field breakdown and thus a higher voltage is induced secondarily. This process is repeated until an overturn occurs on the respective discharge route or routes. Another capacitor of a certain size, connected in parallel with the overturning path in the distributor against 1, leads to a further increase in the ignition voltage and to an almost complete reduction of the magnetic field during the ignition process.

In order to make a high efficiency of the current transmission at the spark gap 14 possible and thus to ensure a maximum filling of the capacitor 12, it is necessary to coat the cathode surface of the distributor finger with metal, which opposes a low work function.

So that it is possible to adapt the impedance of the pulse oscillator ignition system to the particular requirements of the transmission parts to the spark plug tuning plug, a tunable voice coil 19 must be provided parallel to the primary winding 5 of the pulse oscillator. With the spark plug tuning plug, the impedance of the spark plug of the ignition system is adjusted.

It has been found that the power supply of low-resistance ignition coils or ignition transformers is necessary by switching an electrolytic capacitor of certain size 15 to ground 31. This prevents the charging voltage at terminal 15 from falling when the maximum charging current of the ignition coil is reached. As a result, a higher amount of energy can be magnetically stored in the ignition coil.

Brief description of the drawing

• Fig. 1 eine schematische Darstellung einer als Impulsoszillator ausgebildeten Zündspule.
• Fig. 2 eine Impulsoszillator-Zündspule unter Einbezug der Überschlagstrecke im Zündverteiler, wobei der Kondensator 12 als Speicherelement herangezogen wird.
• Fig. 3 wie 2, wobei ein Widerstand 42 bestimmter Größe und Induktivität sowie Kapazität als Dämpfungsglied herangezogen wird.
• Fig. 4 zeigt eine Zündspule normaler Bauart, bei der ein Elektrolytkondensator 32 für die Bereitstellung von hoher Energie sorgt.
• Fig. 5 zeigt eine Zusammenschaltung der Impulsoszillator-Zündspule nach Fig. 1 mit dem Speicherelement 32 nach Fig. 4.
• Fig. 6 zeigt eine Impulsoszillator-Zündspule, bei der der Kondensator 7 derart geschaltet ist, daß der maximale Strom zugunsten der Zeit abgesenkt wird.
• Fig. 7 zeigt eine Verlegung der Schalteinheit in die Plusseite (+) der Impulsoszillator-Zündspule.
• Fig. 8 wie 7, wobei ein Elektrolytkondensator für Energiebereitstellung sorgt (siehe Fig. 4).
• Fig. 9 zeigt eine Impulsoszillator-Zündspule mit geänderter Beschaltung der Primärseite zur besseren Energieversorgung.
• Fig. 10 wie Fig. 9, jedoch mit einer Zündspule normaler Bauart.
• Fig. 11 zeigt eine Impulsoszillator-Zündspulenschaltung nach Fig. 2, jedoch mit Elektrolytkondensator 32 und der abstimmbaren Schwingspule 19 zur Änderung der Funkenstandzeit.
• Fig. 12 zeigt einen Verteilerfinger, dessen Katodenfläche 26 mit Selen oder anderen Halbleitern beschichtet ist, um eine möglichst hohe Stromführung im Lichtbogen zu erreichen.
• Fig. 13 zeigt einen Zündkerzenabstimmstecker, bei welchem mittels Ferritkern 48 die Induktivität der aus Widerstandsdraht gewickelten Anpaßspule 45 der Impedanz der Zündkerze zur Zündanlage angepaßt werden kann.

It shows:

• Fig. 1 is a schematic representation of an ignition coil designed as a pulse oscillator.
• Fig. 2 shows a pulse oscillator ignition coil including the rollover distance in the ignition distributor, the capacitor 12 being used as a storage element.
• Fig. 3 as 2, wherein a resistor 42 of certain size and inductance and capacitance is used as an attenuator.
• Fig. 4 shows a normal type ignition coil in which an electrolytic capacitor 32 provides high energy.
• FIG. 5 shows an interconnection of the pulse oscillator ignition coil according to FIG. 1 with the memory element 32 according to FIG. 4.
• Fig. 6 shows a pulse oscillator ignition coil, in which the capacitor 7 is connected such that the maximum current is reduced in favor of time.
• Fig. 7 shows a shift of the switching unit in the plus side (+) of the pulse oscillator ignition coil.
• 8 and 7, with an electrolytic capacitor providing energy (see FIG. 4).
• Fig. 9 shows a pulse oscillator ignition coil with modified wiring of the primary side for better energy supply.
• Fig. 10 as Fig. 9, but with an ignition coil of normal design.
• FIG. 11 shows a pulse oscillator ignition coil circuit according to FIG. 2, but with an electrolytic capacitor 32 and the tunable voice coil 19 for changing the spark life.
• 12 shows a distributor finger, the cathode surface 26 of which is coated with selenium or other semiconductors in order to achieve the highest possible current flow in the arc.
• FIG. 13 shows a spark plug tuning plug, in which the inductance of the matching coil 45 wound from resistance wire can be adapted to the impedance of the spark plug to the ignition system by means of ferrite core 48.

Ignition coils and pulse oscillator ignition with tunable coil 19, the specific inductance of which is adapted to the respective need by changing the position of the core 21, determine the efficiency of the ignition system. When the ignition current is switched on, the capacitor 32 is charged from point 29 via line 31 and line 2 via point 16 and line 15 to the ignition lock to the battery. By applying a control signal from the control device (contacts) via line 34 to the switching unit 35, the negative side of the capacitor 32 is led via line 31 point 30, line 33 via the switching unit 35 and line 8 to the connection points 20 and 36 of the coils 19 and 5 . From points 18 and 4, line 3 leads the current back via point 17 and line 15 and point 16 with line 2 to the positive plate of capacitor 32. A magnetic field is built up in the cores 10 and 21 by the current flow in the coils 5 and 19. By changing the control signal in the coils 5 and 19, the charging current is interrupted, the magnetic field in both cores begins to collapse. The result of this is that an oppositely directed voltage builds up in the coils 5, 19 and 22. Now point 23 of line 25 and point 24 with line 9 charge capacitor 7. The current flowing in the opposite direction via line 6, point 1, line 2, point 16 and line 15 at point 17 via line 3 at points 4 and 18, now causes an accelerated field breakdown in the cores 10 and 21 Tension increased. When the breakdown voltage is reached at the cathode 26 via line 25, a high-energy arc is formed, which in turn charges the capacitor 12 via anode 27, point 28, line 13. Through the flowing stream Via line 11 and point 1 and line 2, point 16, line 15 "point 17, line 3 to points 4 and 18, a strongly accelerated field breakdown is still caused in the coils. This continues until the through the spark plug The capacitor formed is charged to such an extent that the distance between the electrodes is ionized. An arc is formed from the current of the candle capacitance, which means that the voltage at the candle breaks down (up to approx. 50 V) from the capacitor 12 via the arc path of the distributor finger 40 and the capacitor 7 via line 37, connection point 44 of the plug adapter plug 50, via the winding 45, connection point 46, ensures that the arc is maintained on the candle with the highest energy flowing current is in turn braked by an oppositely directed voltage, which is influenced in this way by the core 48 in the carrier 47 ssen that the current simultaneously from the coatings of the capacitors 12 and 7 and the coil 22 via ground 29, line 31, capacitor 32, line 2, point 16, line 15 and line 2, points 1 and 17, line 3, 6th and 11 flows back into the coils 19 and 5 and the capacitors 7 and 12.

Claims (6)

1. Ignition devices for internal combustion engines and other work machines excited by spark ignition with ignition coil and capacitor, characterized in that between the output of the secondary side and the input of the primary side, the capacitor forms a pulse oscillator. 2. It is possible, according to claim 1, to adapt the impedance of the pulse oscillator ignition to the respective requirements. This is characterized in that a tunable voice coil 19 is to be provided parallel to the primary winding 5 of the pulse oscillator. 3. Pulse oscillator ignition systems according to claim 1, which are equipped with overflow distributors, characterized in that the cathode surface of the distributor fingers are coated with a material which opposes low work function. 4. pulse oscillator ignition systems according to claim 1, characterized in that an attenuator as in Fig. 3 is used as a bandpass filter. 5. pulse oscillator ignition systems according to claim 1, characterized in that a spark plug tuning plug according to FIG. 13 makes an impedance matching of spark plugs to the respective requirements possible. 6. Ignition systems according to claim 1, characterized in that they use an electrolytic capacitor as a storage unit in the low-voltage range as a Niederohnischc ignition coil or pulse oscillator (FIG. 1).

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