SU870754A2 - Battery-type ignition system - Google Patents

Description

(54) BATTERY IGNITION SYSTEM

I

This invention relates to electronic ignition systems for internal combustion engines and is an improvement on a known device.

In the main invention of auth. St. No. 439622 describes a battery ignition system comprising a transistor voltage converter on a transformer with two-transistor trigger, a rectifier, a filling capacitor, a thyristor, an ignition coil and a stabilization circuit on two transistors, the base of one of which is connected to the connection point of the primary winding of the converter transformer and the resistor, and the base of the other to the junction point of the Zener diode and the resistor, and the collector of this transistor is connected through a capacitor to the base of the first transistor trigger ras.

The known ignition system ensures the stability of the secondary voltage when the temperature varies from -60 to + 70 ° C, the voltage of the power supply varies from 6.5 to 17 V and has a high efficiency over the entire range of engine speeds. However, when the supply voltage drops below 6 V at the moment the engine starter is turned on, it is possible to open the power transistor switch controlled by the trigger, while it remains open even if the normal supply voltage is restored after the starter is turned off, until the supply voltage is removed (ignition off) In this case, the engine start becomes impossible, and the ignition system fails as a result of the long passage of a large current through the power transistor switch. This is because when the supply voltage is below 6-6.6 V, the stabilization circuit receives a pulse at the input of the trigger with an amplitude insufficient to transfer the trigger to the second stable state in which the power transistor switch closes.

IS

The purpose of the invention is to improve the reliability of the battery ignition system, with a reduced voltage supply.

This goal is achieved by the fact that the battery ignition system for internal combustion engines according to aut. St.

20 No. 439622 additionally introduced a threshold circuit connected between the emitters of the first and second transistors of the trigger, with

This threshold circuit is made, for example, on a semiconductor diode, the cathode of which is connected to the emitter of the second transistor, and the anode to the emitter of the first transistor, or to a zener diode connected in the opposite direction.

In the drawing, an electrical circuit diagram of the battery ignition system is given.

The ignition system consists of a trigger on transistors 1 and 2 with a threshold circuit 3, a power transistor switch 4-, a voltage converter, which includes a transformer 5 and a diode 6, a stabilization circuit on transistors 7 and 8 and a zener diode 9, an interrupter 10, a storage capacitor 11, a thyristor switch 12, a discharge diode 13, an ignition coil 14, a capacitor 15, a resistor 16, a diode 17, a resistor 18 ,. the capacitor 19, the resistor 20, the diode 21, the resistor 22 and the capacitor 23. The trigger is designed to control the transistor switch 4, which controls the voltage converter. The stabilization circuit captures the moment of current rupture in the converter. The interrupter 10 synchronizes the operation of the ignition system. In the condenser 11, sparking energy is stored. The thyristor 12 connects the charged capacitor 11 to the primary winding of the ignition coil.

The ignition system with a supply voltage of 6.5 to 17 V operates as follows.

After turning on the power, the transistor 7 is open, the transistor 8 is closed, and the trigger is set to the first steady state, in which the transistor 1 is closed and the transistor 2 is open. The power switch 4 then opens, and a linearly increasing current flows through the primary winding of the transformer 5 and the resistor 22. Voltage pulses appear on both halves of the transformer secondary winding. A positive pulse from the beginning of the secondary winding through the capacitor 19, the resistor 20 and the diode 21 is fed to the control electrode of the thyristor 12, but the thyristor remains off, since capacitor 11 is not charged, and the voltage at the thyristor anode is zero. The negative pulse from the end of the secondary winding to the capacitor 11 does not pass,

As the current through the primary winding of the transformer 5 increases, the voltage across the resistor 22 increases, and at the moment that when it reaches the stabilization voltage of the stabilizer 9, the transistor 8 opens, the transistor 7 closes. A negative voltage jump from the collector of the transistor 7 through the capacitor 23 enters the base of the anzistor 1, and the trigger goes to the second steady state — the transistor 1 opens, the transistor 2 closes. This leads to the closing of the power switch 4 and the cessation of the current through the primary winding of the transformer 5. At the same time, the energy stored in the magnetic field of the transformer creates voltage surges in its windings. A positive surge voltage from the end of the secondary winding through diode 6 charges the storage capacitor 11 to a voltage of 350-400 V, which is determined by the magnitude of the breaking current and the inductance of the transformer primary winding and is not dependent on the supply voltage.

With the contacts of the chopper 10 closed, the capacitor 15 is charged through the resistor 16, the diode 17 is closed. At the moment of opening the contacts of the chopper, the charged capacitor 15 through the resistor 18 and the diode 17 is connected to the trigger input. Diode 17 opens, a positive voltage from capacitor 15 goes to the base of transistor 1, and the trigger goes to the first steady state. At the same time, the processes described when switching on the power are repeated, with the difference that at the time of opening the contacts of the breaker, the thyristor 12 switches and connects the charged storage capacitor 11 to the primary winding

ignition coils 14. Threshold circuit 3 with a voltage of 6.5 to 17 volts does not affect the operation of the ignition system.

When starting the starter when starting the engine, the yitani voltage may drop below the minimum allowable

0 for a given ignition system, for example, due to the oxidation of battery terminals. After the starter starts to rotate the engine shaft, the voltage in the on-board network usually rises to 7-11 V, depending on the level of charge of the accumulator battery and the ambient temperature.

When the supply voltage is below 6.5 V, because of the voltage drop on the threshold circuit 3, the base potential of transistor 2 relative to its emitter will not be sufficient to open transistor 2, i.e. the trigger will occupy the only stable state in which transistor 1 is open and transistor 2 is closed. This state will not change even with the arrival of pulses.

 from the capacitor 15 at the moments of opening the contacts of the circuit breaker. Consequently, the power switch controlled by the trigger will also be closed. With a subsequent increase in the supply voltage to 6.5 V and higher work

The Q of the trigger and ignition system is generally restored, ensuring reliable engine start.

Claims (2)

1. Battery ignition system for auth. St. No. 439622, characterized in that, in order to increase reliability with reduced power supply, it additionally introduced a threshold circuit connected between the emitters of the first and second transistors of the trigger. 2. The ignition system according to claim 1, characterized in that the threshold circuit is made, for example, on a semiconductor diode, the cathode of which is connected to the emitter of the second transistor, and the anode - with the emitter of the first transistor, or on the Zener diode, connected in the opposite direction. Sources of information taken into account in the examination 1. USSR Author's Certificate No. 439622, cl. F 02 R 3/04, 1972 (prototype).