DD217580A1 - ELECTRONIC STROKE SYSTEM FOR INTERNAL COMBUSTION ENGINES - Google Patents

Abstract

The invention relates to electronic control systems for internal combustion engines in which several sequential ignition sparks are generated by cyclic energy supply. The extra energy and the spark life can be increased for the purpose of igniting lean mixtures. The time sequence of the ignition spark is adjustable according to the invention. By exploiting the known advantages of the high voltage capacitor Zuendanlage, such as high breakdown voltage, steep Zuendspannungsanstieg and low shunt sensitivity, the proposed variants are particularly suitable for internal combustion engines with high Verdichtungsverhaeltnissen when operating with lean fuel-air mixtures, eg. As for internal combustion diesel engines in the multi-fuel operation, so even when using alternative fuels such as methanol and gasoline-methanol mixtures.

Description

Title of the invention

Electronic ignition system for internal combustion engines

Field of application of the invention. The invention relates to an electronic ignition system in which a plurality of consecutive sparks of high energy are generated. The ignition system is suitable for igniting lean mixtures in gasoline engines as well as in spark ignition diesel engines for multi-fuel suitability and the use of alternative fuels. '· .. _: ·. ;

Characteristic of the known technical solutions .7 It is known that for igniting the fuel-air mixture in internal combustion engines by the ignition system ausr.ei-. To ignite lean G-emische significantly greater ignition energies are required than those in which the air ratio is in the range of stöchioinetrisehen ratio · .. Lifting the demand for high ignition energy, one strives to extend the spark life and the love sensitivity of the plants ·

Conventional ignition systems meet these requirements only conditionally. The known under the name of high-voltage capacitor ignition, has the particular advantage that in addition to the low lifting sensitivity of the system works with a constant on-time, the secondary voltage in a large speed range ·

remains approximately constant 'and even with higher density motors, the required breakdown voltage can be provided ·, j

The essential ITachteil the high-voltage capacitor ignition system, is that the spark life is relatively short, which has an unfavorable effect on the combustion initiation. To extend the spark life and increase the spark energy, an ignition system is proposed in DE-OS 2 340 865, in which the primary winding of the ignition coil consists of several individual windings, which are switched by switching transistors in time sequence. With this circuit, a multi-spark ignition system is realized with inductive energy storage. A special ignition coil and a high circuit complexity for driving the switching transistors complicate the construction of this system.

An extension der.Funkenbrenndauer has also proposed in the magazine "Electronics" 25j 1976 by Everding ignition system · It is described an ignition system that represents a combination of a high-voltage capacitor ignition system and a transistor purge ignition · The energy is the primary side stored inductively and capacitively. In the ignition phase, the capacitor discharge and thus the formation of the spark head and the transmission of the inductively stored energy take place in the first phase. Thus the spark life is extended to (1.0 · ..1,2) ms.

In DE-OS 2 821 084 is to achieve two successive ^; the following ignition pulses proposed the parallel connection of two ignition coils and switching transistors, which are controlled in time offset »With this arrangement, a spark life of 1.5 ms is reached ·, '. ·

In.DE-OS 2 339 7S3, several circuit variants are proposed for prolonging the spark life. The discharge of an electrical energy source connected to the spark discharge path ⁽

inductive character so that the energy sum ignition or · initiation of the spark discharge is supplied essentially by the energy source of a capacitive nature, whereas the energy is supplied to extend the burning time of the power source inductive character ·

Object of the invention

The aim of the invention is to improve the conditions for the ignition of lean mixtures in internal combustion engines with a multi-spark high-voltage condensate ignition system. The ignition system should be suitable both for gasoline engines and for the ignition of hochoktanigen fuels or alternative fuels based on methanol and gasoline-methanol mixtures in their combustion in the diesel engine ·

Explanation of the essence of the invention

Object of the invention is to provide an ignition system with which lean fuel-air mixtures in gasoline engines and hochokt anige fuel-air mixtures can be ignited in diesel engines to achieve their Vielstoffeignung · According to the invention this object is achieved in that the well-known laughing part of the high-voltage capacitor ignition conditions, their low spark life, by the succession of multiple sparks whose distance is adjustable, is compensated · Hach this principle, a sufficient ignition energy is introduced to ignite the mentioned fuel types and ensures the operation of the diesel engine in the multi-fuel principle , With this multi-fuel principle (spark-ignited diesel engine), the entire engine speed range can be used knock-free while achieving full engine power. '(

For the generation of at least two ignition pulses according to the invention in the primary ignition circuit to the currently customary capacitor C1 (Figure 1), a further capacitor C2 with an upstream nied.erohmigen choke L ρaralleIgeschaltet · To suppress transients during the charging process

Ganges of the capacitors, the diode D2 to the inductor L is connected in parallel ·

If the thyristor Th is actuated in the ignition point, the capacitors are discharged via the primary winding of the ignition coil after a first ignition pulse, which is caused by the discharge of the capacitor C1, occurs. Formation of a second, staggered ignition pulse by the delayed discharge of the capacitor C2. The time shift is achieved by tuning the low-impedance throttle to the primary circuit. Existing circuits for high-voltage capacitor ignition systems can be expanded to a two-spark ignition system. ,

For the generation of two sparks of the same energy and spark duration, the circuit of FIG. 2 is suitable. There are ^ parailelgeschaltet two ignition circuits with capacitors G1 and C2. They are charged by a flyback converter via the diodes D1 and D2. At the time of ignition becomes the thyristor. Th1, which leads z discharge of the capacitor C1 and for the induction of a first Zündimpiulses. _With an adjustable via the RC G-IIED R4 / C4 time delay of the thyristor Th2 is triggered, whereby a second ignition pulse is induced · • With-the, laughing to the ignition coil parallelgescha.lt et en diode D3 is extended in known manner, the wireless service life , the circuit variants shown in Fig. 1 and Fig. 2, high-voltage Kondensatorenzündanlagen can realize up to four spark discharges.

Existing "high-voltage capacitor ignition systems can be expanded by adding the above-mentioned components to a multi-spark system.

Exemplary embodiment ''

The invention will now be described by means of embodiments. The following drawings are used for explanation. ^: - Fig. 1; G-rounding-a dual-spark ignition system when using a ¹ -turn thyristor; .

Pig · 2: switching of a two-spark ignition system with flyback converter when using two switching thyristors;

Pig · 3: Circuit of a two-spark ignition system with flyback converter when using a switching thyristor;

Pig · 4: Circuit of a three-spark ignition system with flyback converter in use, of two switching thyristors;

Pig. 5J circuit of a four-spark ignition system with flyback converter when using two switching thyristors;

Pig. δ; Punkenstrom- and Brennspannungsverlauf a two- 'fken ignition system according to Pig. 3 y .. '.'

Pig. 7: 'Punkenstrom- and Brennspannungsverlauf a three- /,. spark ignition lead according to Pig · 4; ,

Pig. 8: Punkenstrom- and Brennspannungsverlauf a four-spark ignition system according to Pig. 6;

Pig. 9J Punkenstrom- and Brennspannungsverlauf a three-spark ignition system according to Pig. 4 with increased Punkenabstand between the second and third discharge.

The generation of ignition pulses according to the invention is based on the principle that by a control part of the switching transistor T1 (Pig · 3) at the ignition with one, depending on the. '. By the, Sinschaltflanke of the current increase, a voltage is induced in the secondary winding of the transformer Tr.A voltage which controls the thyristor via C3 and R4 via the thyristor Th takes place in such a way that two ignition pulses occur in time poles.

Charging der.Kondensatoren CT and C2 in the flyback converter via the diode Dt by the Abschaltflanke in the transformer Tr ,. when the switching transistor T1 is blocked · The time profile of the burning voltage and the spark current is shown in Pig · .6. It becomes clear that the spark life is prolonged and the energy converted in the spark gap increases.

If two ignition circuits Fig. 2 with the capacitors C1 and C2, the thyristors ThI and Th2 formed, two ignition pulses of the same spark life and the same energy can be obtained. When driving through Th1, a pulse of the kind described is induced by the switching edge, which activates the thyristor Th1 via C3 and R5.

The discharge, from C1 leads to a first ignition pulse, the. with, temporal. Delay a second by discharging C2 over Th2. follows · The time interval can be set via R4. The switch-off edge when blocking T1 leads to the charging of the capacitors G1 and C2 via the diodes D1 and D2, which simultaneously disconnect both ignition circuits during the discharge process. 4 and 5 · ·. , -.

In FIG. 4, two capacitors are connected in parallel, which are discharged via Th1 and, as described in FIG. 3, enable two firing pulses, which are supplemented by a third, when Th1 is deactivated in the manner described. The temporal profile of the firing voltage and of the spark current is in FIG The possibility of the spark timing shift is shown in FIG. 9. · .0,8) ms according to the engine characteristics.

In FIG. 5, the circuit has been supplemented by a further charging capacitor C4, whereby four ignition pulses are induced during the discharge of the capacitors CI to C4 in the ignition coil 4. The function of the burning voltage and the spark current of

Four spark ignition system is.in Pig. S shown. With this system a U'unkenstandzeit is achieved to 1.5 ms, when four discharges follow each other directly. Lean displacement of the capacitor discharges can further prolong the spark life.

Claims (5)

Claim of invention. 1. Electronic ignition system for internal combustion engines, ' characterized in that the primary winding of the ignition coil and two parallel capacitors form a resonant circuit, the discharge takes place in Zündseitpunkt via a thyristor offset in time by insertion of a low-impedance inductor inductively tuned. r ^ -O ' 2. Electronic ignition system according to item 1, characterized in that two parallel-connected capacitors are charged by a flyback converter and zwei aufeinanderf Olgende ignition pulses generates werden.werden when the switching thyristor durch'die turn-on of the flyback converter driven. ' becomes. ,. 3. Electronic ignition system according to item 1 and 2, characterized in that two, "parallel" capacitors form separate resonant circuits, which are offset in time via two switching thyristors, discharged by time. Delayed control of a thyristor via an RC element * ·. 4 · Electronic ignition system according to point 2 and, 3 characterized in that three capacitors are connected in parallel in two separate 'resonant circuits, which are discharged over two Sciialtthyristoreh staggered ·. · 5. Electronic ignition system, identified in points 2, 3 and 4   characterized in that 'four capacitors are connected in parallel in two separate resonant circuits, which are unloaded over two switching thyristors offset in time · For this 7 sheets drawings