Electronic "capacitor" ignition, CDI (Capacitor Discharge Ignition) "TAVSAR Company". Refinement of the car ignition circuit Capacitor to help the ignition coil of a carburetor engine

Modern car It's hard to imagine without ignition. The main advantages that the system provides electronic ignition are well known, they are as follows:
more complete combustion fuel and the associated increase in power and efficiency;
reduction of exhaust gas toxicity;
easier cold start;
increasing the life of spark plugs;
reduction of energy consumption;
possibility of microprocessor ignition control.
But all this mainly applies to the CDI system
On at the moment, V automotive industry There are practically no ignition systems based on the accumulation of energy in a capacitor: CDI (Capacitor Discharge Ignition) - also thyristor (capacitor) (except for 2-stroke imported engines). And ignition systems based on the accumulation of energy in inductance: ICI (ignition coil inductor) survived the transition from contacts to switches, where the breaker contacts were simply replaced by a transistor switch and a Hall sensor without undergoing fundamental changes (an example of ignition in a VAZ 2101...07 and in integrated ignition systems VAZ 2108…2115 and onwards). The main reason for the dominant distribution of ICI ignition systems is the possibility of an integral design, which entails cheaper production, simplified assembly and installation, for which the end user pays.
This, so to speak, ICI system has all the disadvantages, the main one of which is the relatively low rate of magnetization reversal of the core and, as a consequence, a sharp increase in the primary winding current with increasing engine speed, and loss of energy. Which leads to the fact that with increasing speed, the ignition of the mixture worsens, as a result, the phase of the initial moment of growth of the flash pressure is disrupted, and efficiency deteriorates.

Partial, but not far best solution This problem is solved by the use of dual and quadruple ignition coils (so-called), thereby the manufacturer distributed the load according to the frequency of magnetization reversal from one ignition coil to two or four, thereby reducing the frequency of core magnetization reversal for one ignition coil.
I would like to note that on cars with an ignition circuit (VAZ 2101...2107), where the spark is formed by interrupting the current in a fairly high-resistance coil with a mechanical breaker, which is replaced by electronic switch from or similar in cars with a high-resistance coil does nothing except reduce the current load on the contact.
The fact is that the RL parameters of the coil must satisfy conflicting requirements. Firstly, the active resistance R must limit the current to a level sufficient to accumulate the required amount of energy at start-up, when the battery voltage may drop by 1.5 times. On the other hand, too much current leads to premature failure of the contact group, therefore it is limited by the variator or the duration of the pump pulse. Secondly, to increase the amount of stored energy, it is necessary to increase the inductance of the coil. At the same time, as the speed increases, the core does not have time to re-magnetize (as described above). As a result, the secondary voltage in the coil does not have time to reach the nominal value, and the spark energy, proportional to the square of the current, sharply decreases at high (more than ~3000) engine speeds.
The advantages of an electronic ignition system are most fully manifested in a capacitor ignition system with energy storage in a container rather than in a core. One of the options for a capacitor ignition system is described in this article. Such devices meet most of the requirements for the ignition system. However, their mass distribution is hampered by the presence in the circuit of a high-voltage pulse transformer, the manufacture of which is known to be difficult (more on this below).
In this circuit, a high-voltage capacitor is charged from a DC/DC converter using P210 transistors; when a control signal is received, the thyristor connects the charged capacitor to primary winding ignition coils, while the DC-DC operating in blocking generator mode stops. The ignition coil is used only as a transformer (impact LC circuit).
Typically, the voltage on the primary winding is normalized at 450...500V. The presence of a high-frequency generator and voltage stabilization makes the amount of stored energy practically independent of the battery voltage and shaft speed. This structure turns out to be much more economical than when storing energy in inductance, since current flows through the ignition coil only at the moment of spark formation. The use of a 2-stroke self-oscillator converter made it possible to increase the efficiency to 0.85. The scheme below has its advantages and disadvantages. TO merits must be attributed:
normalization of secondary voltage, regardless of the crankshaft speed in the operating speed range.
simplicity of design and, as a result, high reliability;
high efficiency.
Disadvantages:
strong heating and, as a result, it is undesirable to place it in the engine compartment. The best location, in my opinion, is the car bumper.
Compared to the ICI ignition system with energy stored in the ignition coil, the capacitor ignition system (CDI) has the following advantages:
high slew rate high voltage;
and a sufficient (0.8 ms) burning time of the arc discharge and, as a consequence, an increase in the pressure of the flash of the fuel mixture in the cylinder, because of this the engine’s resistance to detonation increases;
the energy of the secondary circuit is higher, because normalized by the arc burning time from the moment of ignition (IM) to the top dead center (TDC) and is not limited by the coil core. As a result, better flammability of the fuel;
more complete fuel combustion;
better self-cleaning of spark plugs and combustion chambers;
lack of glow ignition.
less erosive wear of spark plug contacts and distributor. As a result, a longer service life;
confident start in any weather, even with a dead battery. The unit begins to operate confidently from 7 V;
soft engine operation due to only one combustion front.

Winding data:

Assembly technology:
The winding is applied turn to turn over a gasket freshly impregnated with epoxy resin.
After finishing a layer or winding in one layer, the winding is covered with epoxy resin until the interturn voids are filled.
The winding is sealed with a gasket over fresh epoxy resin, squeezing out the excess. (due to lack of vacuum impregnation)
You should also pay attention to the termination of the terminals:
A fluoroplastic tube is put on and secured with nylon thread. On the step-up winding, the terminals are flexible, made with wire: MGTF-0.2...0.35.
After impregnation and insulation of the first row (windings 1-2-3, 4-5-6), a step-up winding (7-8) is wound around the entire ring layer by layer, turn to turn. , exposure of layers, “lambs” are not allowed.
The reliability and durability of the unit practically depends on the quality of the transformer.
The location of the windings is shown in Figure 3.

Details
Practice has shown that an attempt to replace P210 transistors with modern silicon ones leads to significant complications electrical diagram(see 2 lower diagrams on KT819 and TL494), the need for careful adjustment, which after one to two years of operation in severe conditions (heating, vibration) has to be repeated.
Personal practice since 1968 has shown that the use of P210 transistors allows you to forget about the electronic unit for 5...10 years, and the use of high-quality components (especially a storage capacitor (MBGC) with a long-lasting dielectric) and careful manufacturing of the transformer - even for a longer period .

1969-2006 All rights to this circuit design belong to V.V. Alekseev. When reprinting, a link is required.
You can ask a question at the address indicated in the lower right corner.

Literature

A. Kurchenko, A. Sinelnikov

The proposed ignition system differs from that described in the collection “To Help the Radio Amateur,” no. 73 (M.: DOSAAF, 1981) in that the storage capacitor in it is continuously charged, and therefore leaks in the secondary circuit elements do not affect the operation of the system.

The system is noise-resistant; works fine if available on-board network pulse interference with an amplitude of up to 80 V.

The multiple sparking mode is not provided. Switching from an electronic system to a conventional battery system is done using plug connectors.

The system provides a stabilized secondary voltage of 360±10 V when the supply voltage changes from 6.5 to 15 V, as well as when the temperature changes from -40 to +70 °C.

The current consumed by the system varies linearly from 0.4 A when the engine is stopped to 1.8 A at four-stroke shaft speed four-cylinder engine, equal to 6000 rpm.

The duration of the spark discharge is 0.3 μs, and its energy is not less than 5.9 mJ.

The electrical circuit diagram of the ignition device in question is shown in Fig. 1.

The ignition system consists of a breaker Pr, an electronic unit EB, a switching device from electronic ignition to battery-powered, consisting of plug connectors XP1, XS1, XP2, ignition coil KZ, ignition switch VZ, battery GB, starter switch VSt.

The electronic unit, in turn, consists of the following main components:
single-ended voltage converter on transistor VT2 and transformer T1;
stabilization device consisting of a VD9 zener diode and an amplifier DC on transistors VT1 VT3, VT4, VT5;
storage capacitor C3

a switching device consisting of thyristor VS1, control transformer T2, resistors R5, R6, capacitor C2 and diode VD8;
discharge diode VD7.

The device works as follows. Let us assume that the contacts of the breaker Pr are open at the moment the power is turned on. After turning on the power, the voltage converter starts working. There is no voltage on storage capacitor C3 at this time, so the zener diode VD9 and transistor VT3 are closed. Transistors VT4, VT5 are open. The first of them is the current into its base through resistor R11, and the second is the collector current of transistor VT4 into its base through resistor R14. The open transistor VT5 bypasses the base-emitter junction of transistor VT1, as a result of which the latter is closed and does not affect the operation of the converter. Transistor VT2 of the converter initially opens with current into its base through resistor R1. In this case, the full supply voltage is applied to winding 1 of transformer T1. Voltages are induced in the remaining windings of the transformer. The negative voltage from the beginning of winding II (the beginnings of the windings in the diagram in Fig. 1 are indicated by dots) through diode VD5 and resistor R2 is supplied to the base of transistor VT2 and puts transistor VT2 into saturation state. A linearly increasing current begins to flow through winding I of transformer T1 (t1 in Fig. 2).

Which we will call the interruption current, transistor VT2 begins to turn off. The voltage on it increases, and on winding I decreases. As a result, the voltage on winding II also decreases, which speeds up the process of turning off transistor VT2, which turns off within a few microseconds. The voltage in the windings of transformer T1 changes its sign. Positive voltage from the beginning of winding II is applied through resistor R4 to the base of transistor VT2 and reliably locks it. The current through transistor VT2 and winding I of transformer T1 stops (t2 in Fig. 2). This ends the direct operation of the converter. During forward stroke, reverse voltage is applied to diode VD6 from winding III, so the diode is closed and the secondary circuit (elements located in the diagram of Fig. 1 to the right of diode VD6) does not affect the operation of the converter.

Rice. 2. Timing diagrams of the operation of a single-cycle stabilized voltage converter: UIII, Uc3 - voltage, respectively, on winding III and capacitor C3, i1, - current through winding I of transformer T1

After the current is interrupted in winding I of transformer T1, the reverse operation of the converter begins.

The energy accumulated in the magnetic field of the transformer creates voltage pulses of opposite polarity in its windings. A positive pulse from the beginning of winding III opens the diode VD6 and charges the storage capacitor to a voltage depending on the energy accumulated in the magnetic field of the transformer during forward stroke and the capacity of the storage capacitor (t3 in Fig. 2).

If we assume that all the energy accumulated in the magnetic field of transformer T1 during the forward stroke is converted into the energy of the electric field of the capacitor, then the voltage to which the storage capacitor is charged will be equal to:

Where ir is the strength of the rupture current; L1 - inductance of winding I.

The duration of the reverse pulse also depends on the energy accumulated in the transformer and the capacitance of the storage capacitor C3 and, in addition, as can be seen from Fig. 2, it decreases as the pulse amplitude increases. Indeed, the energy of each pulse is constant - L1(ip) squared/2, therefore, the area of ​​the pulse is constant, but the height of the pulse increases all the time and, therefore, its duration should decrease.

After the end of the reverse pulse (t4 in Fig. 2), the positive voltage in the windings of transformer T1 disappears, transistor VT2 opens again and the above processes are repeated.

The voltage across the storage capacitor increases stepwise. When it reaches a given value of 350...360 V (t5 in Fig. 2), which is determined by the resistance of resistors R7, R8, R9 and the stabilization voltage of the zener diode VD9, the latter opens. Transistors VT3, VT1 open, and transistors VT4, VT5 close. Positive feedback, carried out through resistor R12, speeds up the process of switching transistors VT1, VT3, VT4, VT5 of the relay amplifier and, in addition, increases its stability. Capacitor C4 also increases the stability of the amplifier.

The collector-emitter transition of the open transistor VT1 through the diode VD1 bypasses the emitter-base transition of the transistor VT2, as a result of which the latter closes and the converter stops working. The storage capacitor is slowly discharged through resistors R7, R8, R9, zener diode VD9 and leakage resistances of thyristor VS1, diodes VD6, VD7 and its own insulation resistance. After some time, the voltage on the storage capacitor decreases so much that the zener diode VD9 closes. Transistors VT3 and VT1 of the relay amplifier close, and transistors VT4, VT5 open. The converter starts working again (t6 in Fig. 2). The very first reverse pulse recharges the storage capacitor, the voltage on it increases and the zener diode VD9 and transistors VT3 and VT1 open again. The converter stops working again, etc.

Thus, intermediate level The voltage across the storage capacitor is maintained constant. When the supply voltage decreases, the strength of the interruption current - ip - decreases, and therefore the energy accumulated in the magnetic field of the transformer during the forward stroke decreases. However, at the same time, the operating frequency of the converter increases and the storage capacitor begins to be recharged more often. As a result, the average voltage level across it remains constant. For example, tests have shown that when the supply voltage increases from 6.5 to 15 V, i.e. by 230%, the voltage on the storage capacitor increases by only 2%, from 360 to 367 V.

The same thing happens when the leakage current in the secondary circuit increases. The storage capacitor begins to discharge faster, but is also recharged more often. As a result, the average voltage level across it remains constant.

The ripple amplitude, or the magnitude of the voltage step on the storage capacitor, in steady state depends on the energy stored in the magnetic field of the transformer during the forward stroke. The lower this energy, the smaller the size of the step. In practice, the size of the step should not exceed 10...15 V. Otherwise, the sparking voltage turns out to be practically unstabilized. Indeed, since the operation of the converter is not stabilized with the operation of the breaker, the contacts of the latter can open at any time. From Fig. 2 it can be seen that the voltage supplied to the ignition coil will be greater if the breaker opens at moment t5 rather than t7. If the amplitude of the step, for example, is 70 V, then the sparking voltage cannot be considered stabilized.

The second, and at the same time very important requirement for the converter, if it is intended to work in the ignition system, is its speed. He must have time to charge the storage capacitor during the time between two sparks, at a maximum sparking frequency of 200 Hz, i.e. in 5 ms.

The speed of the converter is mainly determined by the strength of the breaking current ip. .The larger it is, the greater each portion of energy and the faster the storage capacitor charges. In this case, however, the rise time of the current also increases. However, the latter increases in proportion to the first power of the current, and the energy is proportional to the square of the current. Therefore, the total charging time of the storage capacitor decreases with increasing breaking current. The speed of the converter practically does not depend on the inductance of the primary winding I of the transformer. The greater the inductance, the greater each portion of energy, but the current increases just as slowly. The forward running time increases. When the inductance of winding I increases, for example by increasing the cross-section of the transformer core, the operating frequency of the converter decreases, the capacitor is fully charged, for example, in 3-4 reverse pulses, but the total charging time is the same as with a lower inductance, when the capacitor is charged in 10-15 pulses. At the same time, the size of the step in steady state in the first case is larger and, in addition, the transformer has large dimensions and weight.

Therefore, the design of the converter transformer can be very different. It is only necessary that the losses in copper (in winding I) be approximately equal to the losses in steel (in the core), which can be determined by the degree of heating of the winding and core (they should heat up approximately equally). In addition, the frequency of operation of the converter in unsteady mode (t1 - t5 in Fig. 2) should not exceed 10... 15 kHz, since as the frequency increases, the losses in the transistor VT2 and the transformer core increase.

As the supply voltage decreases, the breaking current decreases and, consequently, the total charging time of the storage capacitor increases. However, at the same time, the frequency of spark formation is low, for example, when starting the engine with the starter, and the storage capacitor still manages to be fully charged.

Let us dwell on the purpose of some elements of the converter.

Diode VD1 protects transistor VT1 from voltage of positive polarity appearing in winding II (based on transistor VT2) during reverse stroke.

Diode VD4 compensates for the voltage drop across diode VD1, which is necessary for reliable locking of transistor VT2 when unlocking transistor VT1.

Thanks to the diode VD5, connected in parallel with resistor R4, the negative half-wave of voltage from winding II passes to the base of transistor VT2 through this diode almost completely, and the positive half-wave is limited to a level acceptable for transistor VT2 by diodes VD2, VD3.

When the breaker contacts are closed, current begins to flow through resistors R5, R6 and diode VD8. The voltage on winding I of transformer T2 is limited by the diode VD8, and therefore the amplitude of the negative pulse on the control electrode of thyristor VS1 at the moment the breaker contacts close does not exceed 0.35 V. Limiting the voltage on winding I, in addition, ensures an increase in the current rise time.

Resistors R5, R6 limit the current through winding I and, together with capacitor C2, form a low-pass filter that provides the necessary noise immunity to the ignition system.

By the time the breaker contacts open, the current in winding I reaches a steady-state value. Electromagnetic energy accumulates in the core of transformer T2. Therefore, at the moment the contacts open, voltage pulses appear in the transformer windings. A positive pulse from the end of winding II goes to the control electrode of thyristor VS1, as a result of which the latter switches (t1 in Fig. 3).

Rice. 3. Time diagrams of the operation of the ignition system with continuous accumulation of energy at the moment of conversion: Uc3 - voltage on the storage capacitor C3, Is - current through the primary winding of the ignition coil, Ucv - voltage on the spark plug in the winding, which eliminates the influence of bouncing of the breaker contacts.

The primary winding of the ignition coil is connected to a storage capacitor C3 charged to a voltage of 350 V, and the voltage on it increases to 350 V (Uk) within a few microseconds. The rate of rise of the secondary voltage depends on the parameters of the ignition coil. When using serial coils from a conventional battery ignition system (for example, B117), a spark occurs 3...5 μs after the breaker contacts open (t2 in Fig. 3).

The inductance of the primary winding of the ignition coil and storage capacitor C3, connected to each other through a switched thyristor, form an oscillatory circuit in which damped oscillations occur. The current in the circuit is Isk, flowing at this time through the thyristor and the primary winding of the ignition coil, as can be seen from Fig. 3, lags the voltage by 90°. After a quarter of the period, at time t3, the current in the circuit reaches a maximum, and the voltage on the capacitor becomes zero, and then changes its sign and becomes negative. As soon as the voltage on the storage capacitor becomes negative, diode VD6 opens and current Ivd6 begins to flow through it and winding III of transformer T1, loading the converter and preventing it from starting to work. After half a cycle, at time t4, the current in the circuit becomes zero and the thyristor turns off. However, thanks to the VD7 diode, the oscillatory circuit is not destroyed. The voltage on the storage capacitor at this time (t4 in Fig. 3) is negative, the diode VD7 opens and the circuit current now flows through it.

After another half cycle at time t5, the current in the circuit again decreases to zero, the diode VD7 closes and the oscillatory circuit is destroyed. The primary winding I of the ignition coil is disconnected from the storage capacitor, and the spark discharge in the spark plug stops. However, diode VD6 remains open for about 150 μs until the energy accumulated in the magnetic field of transformer T1 (due to current Ivd6 flowing through winding III) is spent on recharging the storage capacitor (t5 -t6 in Fig. 3). As can be seen from Fig. 3, at moment t5, when the diode VD7 closes and the oscillatory circuit is destroyed, there is a positive voltage U2 across the storage capacitor, which is approximately 30% of the initial voltage U1. The voltage value U2 is determined by the energy released in the spark discharge of the spark plug, which can be calculated using the formula

The energy released in a spark discharge, other things being equal, depends on the size of the spark gap of the spark plug. As the size of the spark gap increases, the voltage U2 decreases and, consequently, the energy released in the spark discharge increases.

From Fig. 3 it can be seen that the duration of the spark discharge in the described system (when working with the B117 coil) is approximately 0.3 ms. Moreover, the spark discharge consists of two parts - positive and negative, corresponding to the positive and negative half-waves of the current in the primary winding of the ignition coil.

The relatively short duration of the spark discharge is not a disadvantage of the described system. As studies have shown, in a serviceable and correctly calculated engine, after reaching normal thermal conditions, ignition of the working mixture occurs within 10... 15 μs, and a spark discharge lasting more than 1 ms, which occurs in battery or transistor ignition systems, is useless and only causes erosion spark plug electrodes, reducing their service life. A spark lasting 1.0 ms or more can be useful only when starting the engine with an over-rich mixture, both hot and cold.

It should be noted here that in the described ignition system with a single-cycle converter, the duration of the spark discharge cannot be increased by connecting diodes in parallel with the primary winding of the ignition coil, as is done in the system with pulsed energy storage described in VRL No. 73.

When diodes are connected, the system stops working. The current consumption increases to 3 A, and sparking stops. This occurs because the voltage across the storage capacitor no longer becomes negative during sparking. The converter continues to work all the time and the switching thyristor does not turn off. The converter turns into a current generator that powers the thyristor.

The voltage on the storage capacitor is equal to the voltage drop in the switched thyristor.

In order for the system to work with a diode, it must be equipped with additional device, for example, a inhibited multivibrator that blocks transistor VT2 of the converter for the duration of the spark discharge.

Construction and details. The design of the electronic unit can be very arbitrary. However, the block body must be made of aluminum alloy, which will provide good heat dissipation for heating elements. In addition, it must be splash-proof, since water ingress during operation is not excluded.

The cooling radiators must have transistor VT2, diodes VD4 and VD7, and thyristor VS1 installed. The remaining elements are located on printed circuit board. The XP1 connector is installed on the unit body. From the XP1 connector comes a harness of wires of various lengths and colors for connection to the corresponding circuit points on the car. The XP2 connector is closed on the mounting side with a cylindrical plug, and on the pin side with a cover with a chain (so that the cover does not get lost), and is secured to the wiring harness of the XS1 connector.

Connectors XP1, XP2 are used 2РМ 18B 7Ш1В1, connector XS1 - 2РМ. 18KPN 7G1V1.

Types of semiconductor devices, resistor ratings and powers, as well as capacitor ratings are indicated in the diagram in Fig. 1. Fixed resistors are used like MLT. Variable resistor R8-SP5-1a, SP5-2. The temporary stability of the secondary voltage of the unit depends on the quality of this resistor, on its temporary stability.

Capacitors C1, C4 can be of any type: mica, film, ceramic, metal paper, etc., but must be non-electrolytic, for a voltage of at least 50 V, with any permissible deviation of the capacitance from the nominal value and any temperature coefficient of the capacitance. Capacitor C1, for example, can be MBM-160-0.05 ± 20%, and capacitor C4 can be BM-2-200V-0.01 ± 20%.

Capacitor C3 - MBGCh, MBGO, MBGP for voltages less than 500 V. You can also use two MBM capacitors of 0.5 μF for 500 V, connecting them in parallel.

Electrolytic capacitors C2 and C5 K50-20, K53, K52 for a voltage of at least 25 V and a capacity not less than indicated in the diagram.

Transformer T1 has a core Ш16x16 (section 256 mm2) made of steel E330, E340, E44, which is assembled end-to-end with a non-magnetic gap of 0.15...0.25 mm (pressed span gasket).

Winding I has 16 turns of PEV-2 wire with a diameter of 0.9...1.12 mm, winding II has 11 turns, and Winding III has 290 turns of PEV-2 wire with a diameter of 0.35...0.47 mm.

For transformer T1, a core with a different cross-section can be used. For example, from a unit with pulsed energy storage (VRL No. 73). In this case, the turns of the windings change in inverse proportion to the square root of the ratio of the cross-sections of the cores. Transformer T1 must be well tightened with a special clip. Otherwise, it will create a lot of noise when the system operates.

Transformer T2 is made on a toroidal core OL12X20X6.5 made of steel E330, E340. Winding I has 150 turns of PEV-2 wire with a diameter of 0.33 mm, and winding II has 75 turns of the same wire, but with a diameter of 0.15 mm.

When replacing transistors and diodes, you should be guided by their operating modes, which are given in table. 1 (diodes) and table. 2 (transistors).

As an example, these tables show some options possible replacement. When replacing transistor VT2 KT837V with KT837A(B), the operation of the unit deteriorates.

Due to the low current gain of the replacement transistors, the breaking current ip decreases (see Fig. 2) and, as a result, the charging time of the storage capacitor increases. The system performance decreases and, in addition, its minimum operating voltage increases.

When replacing transistor VT4, you should choose a transistor with a maximum collector-emitter voltage, since its collector at some points in time (t6 -t7 in Fig. 2) experiences the full voltage of the on-board electrical network with impulse noise several times higher than the rated on-board voltage.

Instead of the KS191Zh (VD9) zener diode, any other zener diode with a minimum stabilization current of no more than 0.5 mA can be used. For example, KS175Zh, KS210Zh, 2S191Ts, 2S210Ts, etc. If the stabilization voltage of the replacement zener diode differs significantly from the stabilization voltage of the KS191Zh zener diode (7.7...9.6 V), then some change in the resistance of resistors R7, R9 may be required.

When setting up the unit, the ignition coil with a spark gap and the breaker must be connected according to the diagram in Fig. 1. The standard capacitor C must be disconnected from the breaker terminal. Instead of a breaker, any polarized relay (for example, RP-4) can also be used, the winding of which is connected to a sound generator or to the network AC 50 Hz, 220 V (in the latter case - through a damping resistance or a step-down transformer).

A starter battery or any stabilized DC power source with a voltage of 6.5 to 15 V and a current of at least 5 A is used as a power source, for example VS-26, B5-21, etc.

Before turning on the power, the variable resistor R8 slider is set to the top position in the circuit so that the voltage on the storage capacitor C4 is initially minimal. A DC voltmeter with a voltage of 500 V with a current consumption of no more than 100 μA (with an input resistance of at least 5 MΩ) is connected parallel to the plates of capacitor C4.

The initial check of the unit is carried out with a supply voltage of 12...14 V and open contacts of the breaker. If the unit is assembled correctly and all parts are in good working order, it starts working immediately and setting it up only consists of setting the required voltage on the storage capacitor using the variable resistor R8. After turning on the power, a characteristic “squeak” of a pure tone should be heard, which is a consequence of the operation of the converter.

By rotating the axis of the variable resistor R8, set the voltage on the storage capacitor to 350...360 V. In this case, the current consumed by the unit should not exceed 0.5 A. Then check the operation of the converter at extreme values ​​of the supply voltage 6.5 and 15 V. When When the supply voltage changes within these limits, the voltage on the storage capacitor should remain practically constant. Only the tone of the “squeak” and the current consumption should change, which at 6.5 V should be no more than 1.5 A, and at 15 V - no more than 0.5 A.

Then the DC voltmeter is disconnected and the operation of the ignition system is checked at different frequencies rotation of the distributor shaft (at different sparking frequencies). During operation of the breaker, a stable spark should be observed in the spark gap of the arrester. The voltage supplied to the primary winding of the ignition coil can be measured using a pulse voltmeter or oscilloscope. Set the power source voltage to 14 V and increase the operating frequency of the breaker (or a device that replaces it) to 200 Hz (6000 rpm), while the voltage supplied to the primary winding of the ignition coil should not decrease. If it decreases, this means that the converter does not have time to fully charge the storage capacitor, i.e., the speed of the converter is not enough. In this case, the non-magnetic gap in the transformer core should be increased or the number of turns of all windings should be proportionally reduced in order to reduce the inductance of winding I. In addition, this can occur if the current gain of transistor VT2 is small. Then it is necessary to replace the transistor or reduce the resistance of resistor R2 to 10 Ohms.

Installation on a car. On a car, the electronic unit is installed in the engine compartment, where the temperature does not exceed +60°C and where direct ingress of water is excluded.

The wires of the XS1 harness are connected to the corresponding points of the vehicle electrical circuit in accordance with the diagram in Fig. 1, which shows the connection to the B117 coil without an additional resistor (Zhiguli cars). The wire from pin 2 in this case remains free.

If the coil has an additional resistor, then pin 2 is connected to the coil terminal VK, and pin 7 to the VK-B terminal.

When installing the unit on VAZ-2103, 2106, 21021 models that have an electronic tachometer, the brown tachometer wire is connected to terminal 1 of the coil through an MLT resistor with a resistance of 1...3 kOhm and a power of 1 W. When connected directly, the tachometer is unstable.

The standard capacitor from the breaker terminal must be disconnected and connected to pin 6 (connector XS1). After installing the unit on the car and checking its functionality, you should check the switching device from electronic to conventional ignition. To do this, with the ignition off, disconnect connector XS1 from connector XP1 and connect it to connector XP2. The ignition system should continue to function properly.

Attachment to the electronic unit of a capacitor ignition system with continuous energy storage to obtain multiple sparks

The attachment provides multiple sparks when starting the engine with a starter. The first spark occurs, as usual, after the breaker contacts open, followed by a series of sparks until the contacts close. A distinctive feature of the console is that it does not contain its own autogenerator and the frequency of multiple sparking is determined by the speed of the ignition system itself. Each subsequent spark occurs only after the storage capacitor is fully charged. If the storage capacitor is not fully charged, the multiple sparking mode stops and the system operates in single-shot mode.

The electrical circuit diagram of the attachment with connection circuits on the car is shown in Fig. 4. The set-top box itself consists of a symmetrical trigger on transistors VT7, VT8, an electronic switch simulator of breaker contacts on transistors VT9, VT10 and a pulse inverter on transistor VT6. The set-top box is connected to the electronic unit as shown in Fig. 4. In this figure, the elements of the ignition system and the elements of the electronic unit are indicated in the same way as in Fig. 1: EB - electronic unit, VZ - ignition switch, VSt - starter switch, Pr - breaker, GB - battery. The remaining elements and circuits of the ignition system in Fig. 4 are not shown because they work the same as without the prefix.

Rice. 4. Schematic diagram consoles

In Fig. Figure 5 shows timing diagrams characterizing the operation of the device with the set-top box. The system works as follows. Let us assume that at the moment the starter switch is turned on, supplying power to the console, the contacts of the breaker Pr are closed (t1 in Fig. 5). After turning on the power, the trigger on transistors VT7, VT8 can be set to any state. Let's assume that VT7 is closed and VT8 is open. We will call this state of the trigger the first stable state.

Rice. 5. Time diagrams of the operation of the ignition system with continuous energy accumulation in the multiple sparking mode (with an attachment):

Consequently, transistor VT9 will be closed, and transistor VT10 will be opened by current flowing into its base through resistor R27. The collector current of transistor VT10 flows through resistors R5, R6 of the electronic unit and winding I of transformer T2, and electromagnetic energy accumulates in the transformer core. Moreover, if the trigger is established in the second stable state and the transistor VT10 is closed, the current of winding I will flow through the diode VD16 and the closed contacts of the breaker.

The first opening (t2 in Fig. 5) of the breaker contacts, if transistor VT10 is open, will not change the state of the elements in the device. When the contacts of the breaker are closed, capacitor C12 is charged through the emitter-base junction of transistor VT6, resistor R17 and diode VD11. Transistor VT6 opens for a short time and positive impulse from its collector through resistor R19, capacitor C6 and diode VD13 it goes to the base of transistor VT7. The trigger switches to the second stable state (t3 in Fig. 5), transistor VT7 opens, and transistor VT8 closes. Transistor VT9 opens with current into its base through resistors R24, R26, and transistor VT10 closes. The current of winding I of transformer T2 now flows through the diode VD16 and the closed contacts of the breaker.

At the moment the breaker contacts open, as usual, sparking occurs in the system (t4 in Fig. 5), in addition, the positive pulse generated in winding I of transformer T2 passes through capacitor C10, diode VD14 and resistor R22 to the base of the transistor VT8, and the flip-flop switches back to the first stable state. Transistor VT8 opens and, consequently, transistor VT10 opens, which is equivalent to closing the contacts of the breaker. Through winding I of transformer T2 begins to flow collector current transistor VT10.

After sparking in the spark plug stops (t5 in Fig. 5), the converter begins to work and at time t6 charges the storage capacitor to a set voltage of 350...360 V. As soon as the voltage on the storage capacitor reaches the specified value (t6 in Fig. 5), The zener diode VD9 (see Fig. 1) of the stabilization device of the electronic unit opens, transistors VT3, VT4, VT5 of the relay amplifier are switched, and transistor VT4 closes, and the voltage on its collector suddenly becomes positive. A positive pulse from the collector of transistor VT4 through capacitor C8 and diode VD13 is supplied to the base of transistor VT7. The trigger switches to the second stable state - transistor VT7 is unlocked, and transistors VT8 and VT10 are locked. Locking the VT10 transistor is equivalent to opening the breaker contacts. A second spark occurs in the system. At the same time, a positive pulse from the collector of transistor VT10 through capacitor C10, diode VD14 and resistor R22 is supplied to the base of transistor VT8, as a result of which the trigger switches again to the first stable state (t7 in Fig. 5). Transistor VT7 closes and transistor VT8 opens. As a result, the voltage on the collectors of transistors VT7, VT8, VT10 takes the form of short pulses lasting several microseconds. In Fig. 5, the duration of these pulses (for greater clarity) is conditionally increased.

After the end of sparking, the storage capacitor is charged again and, when it is charged to a given voltage (t8 in Fig. 5), the transistor VT4 of the electronic unit is turned off and a positive pulse from its collector again transfers the trigger to the second stable state. A third spark appears in the system. Then the above processes are repeated until the breaker contacts close (t9 in Fig. 5).

At the moment the breaker contacts close, a positive pulse arrives at the base of transistor VT7 from the collector of transistor VT6, and the trigger switches to the second stable state. Transistor VT7 opens, and transistors VT8 and VT10 close. However, a spark does not occur in the system, since transistor VT10 at this time is bypassed by the closed contacts of the breaker, and the current through winding I of transformer T2 does not stop.

The positive pulse that appears on the collector of transistor VT4 and arrives at the base of transistor VT7 at the moment the charging of the storage capacitor ends (t10 in Fig. 5) will also not change the state of the elements in the device, since the trigger is already in the second stable state.

Thus, in the multiple sparking mode, when the breaker contacts are open, the signal for each subsequent spark is a positive pulse that appears on the collector of transistor VT4 at the moment the charging of the storage capacitor ends. If, for some reason, the storage capacitor, for example, due to low supply voltage at a high crankshaft rotation speed, does not have time to fully charge before the breaker contacts close and the indicated impulse does not occur, then at the moment the contacts close, thanks to the impulse from the inverter on transistor VT6, the trigger will switch to the second stable state - transistor VT7 will be unlocked, and transistors VT8 and VT10 will be locked, and the system will be able to operate in single-spark mode. Without a pulse inverter on the VT6 transistor, the ignition system in this case would stop working altogether. Transistor VT10 would be open all the time until the storage capacitor began to fully charge again.

Diodes VD10, VD12, VD15 are designed to discharge capacitors C12, C6, C8, C10 after the end of the operating pulses.

Resistors R17, R19, R22, R26 limit the base currents of the corresponding transistors to an acceptable level.

Resistor R25 and capacitor C11 form a low-pass filter that protects the console from impulse interference from the vehicle’s on-board electrical network, the intensity of which increases during starter operation.

Construction and details. The set-top box does not have elements that heat up during operation, so all the elements are located on a printed circuit board or circuit board made of PCB with contact petals, which is placed in some kind of metal casing or box that protects the board from water, dust, etc.

The set-top box can also be assembled in one housing with an electronic unit.

The types of semiconductor devices, as well as the values ​​of resistors and capacitors are indicated in the diagram in Fig. 4. All MLT resistors. Capacitors of any type for a voltage of at least 25 V. Electrolytic capacitor C11 must have a capacity of at least 20 μF and allow operation at temperatures from -30 to +60 ° C.

All instructions given above regarding the elements of the electronic unit and their possible replacement remain valid in this case.

Setting up and installation on the car. If the attachment is assembled correctly and its parts are in good working order, then it starts working immediately and does not require any adjustment. The functionality check should be carried out together with a working electronic unit assembled according to the diagram in Fig. 1. This requirement is due to the fact that the electronic unit for working with the set-top box requires some modification. It is necessary to remove two wires from the block - from the collector of the traisistor VT4 and from pin 1 of the XP1 connector, which are connected to the same terminals of the set-top box. The attachment is connected in accordance with the diagram in Fig. 4. The wire from the breaker is broken and its ends are connected to the terminals of the console 4 and Ave.

The performance test is carried out at a supply voltage of 12... 15 V and a sparking frequency of no more than 20 Hz (no more than 600 rpm).

First, the operability of the system is checked in the single-spark mode, i.e., with the VSt switch open, then it is turned on. The current drawn by the system should immediately increase and the sparking sound should change. It is convenient to monitor the operation of the system using an oscilloscope by connecting it through a voltage divider parallel to the primary winding of the ignition coil.

When operating in the single spark mode, pulses with an amplitude of about 350 V should be observed on the oscilloscope screen, the repetition frequency of which is equal to the opening frequency of the breaker contacts. When the VST switch is turned on, the number of pulses should increase: approximately half of the period should be filled with pulses.

The operation of the attachment can also be checked directly on the car, using an electronic tachometer that measures the frequency of spark formation, or “spark”. In the latter case, disconnect the central high-voltage wire of the distributor and bring it closer to a distance of 10...15 mm to the engine ground. The output of block 1 - VST is not connected at first. Then, rotating the engine shaft with the starter and observing the sparking between the central wire and ground, “on the fly” connect pin 1 - VSt. The sparking sound and spark color should change.

Literature
Glezer G. N., Oparin I. M. Automotive electronic ignition systems. - M.: Mashinostroenie, 1977.
Sinelnikov A. X. Electronic ignition unit of increased reliability - To help the radio amateur. Vol. 73, p. 38-50.
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Car ignition is a set of devices and instruments that ensure ignition of the combustible mixture in the cylinders in accordance with engine operating modes. I'll tell you what this coil is, how important it is correct work for the ignition system. Let's look at what the ignition coil connection diagram looks like, and what it actually consists of.

The ignition coil is a transformer whose operation is aimed at increasing direct current. Its main task is to generate high-voltage current, without which ignition of the fuel mixture is not possible. Current from the battery flows to the primary winding. It consists of one hundred or more turns of copper wire, which is insulated with a special substance. Low voltage voltage (twelve volts) is supplied to the edges. The edges are connected to the contacts on its cover. On the secondary, the number of turns is much larger (up to thirty thousand) and the wire is much thinner. A high voltage is created on the secondary (from twenty-five to thirty thousand volts) due to the thickness and number of turns.

It is connected like this: the contact of the secondary circuit is connected to the negative contact of the primary, and the second contact of the winding is connected to the neutral terminal on the cover, it is this wire that is the transmitter high voltage. A high-voltage wire is connected to this terminal, the other edge of which is connected to the neutral terminal on the cover. To create more power magnetic field, between the windings there is an iron core. The secondary winding is located inside the primary.

Structurally, the ignition coil consists of the following elements:

• Insulator;
• Frame;
• Insulating paper;
• Winding (primary and secondary);
• Insulating material between windings;
• Primary winding output terminal;
• Contact screw;
• Central terminal;
• Lid;
• Output terminal on the primary and secondary windings;
• Center terminal spring;
• Primary winding frame;
• External insulation on the primary winding;
• Mounting bracket;
• External magnetic circuit and core.

So, briefly about the principle of operation.

A high voltage current appears on the secondary winding, and at this moment a high voltage current passes through the primary winding. low current. Thus, a magnetic field arises, as a result of which a high voltage current pulse appears on the secondary winding. At the moment when it is necessary to create a spark, the contacts of the ignition breaker open, and at this moment the circuit opens on the primary winding. A high-voltage current arrives at the central contact of the cover and rushes into the contact near which the slider is located.

The connection diagram is quite simple for a specialist, but it is easy for a beginner to get confused in it.

When connecting the coil to the car’s ignition system, in principle, you should not have any difficulties if, during preliminary dismantling, you marked or remembered which wires are connected where. If you have not done this, then I will tell you how to do it. The connection is made as follows: you need to connect the brown wire to the positive terminal. Usually, the positive terminal is indicated by a “+”, but if you do not see a sign, then you need to find it yourself.
To do this, you can use an indicator screwdriver. I think you know how to use it. It is important that before connecting, clean all contacts and check the wires for serviceability. The black wire is connected to the second terminal (terminal “K”). This wire is connected to the voltage distributor (distributor).

The connection diagram of several elements is as follows. One of the ends of the coil is connected to the on-board network. The second end is connected to the next one, and in this way every last one is connected. The remaining free contact of the last coil must be connected to the distributor. And a common point is connected to the voltage switch. Once all mounting bolts and nuts are securely tightened, the replacement can be considered complete.

Some important tips before replacing and connecting. If you have determined for yourself that the problem with the ignition malfunction is the coil, then it is better to immediately purchase a new one and connect it (the diagram is shown above). This way you will be sure that now there are no problems with it, since it is completely new.

If you find any defects on the surface, it is better to replace it immediately. Otherwise, it will work for some more time and you will have to return to this topic again. It’s better to play it safe in advance so as not to stop somewhere on the road. After all, ignition of a car does not forgive mistakes and negligence.

When repairing a car, especially when it comes to the ignition system, you need to be extremely careful in your actions. Because you may encounter high-voltage wires. Therefore, when replacing or performing repairs, you must follow safety regulations.

Video “Ignition coil connection diagram”

The recording shows how you can connect the coil yourself.

The capacitor is a small but important part electronic systems car. He is responsible for accumulation and preservation electric current, creates a certain voltage indicator in the components and solves a number of other problems. Unfortunately, this product sometimes fails. Working with electrical components is dangerous, but if necessary, the functionality of the capacitor can be easily checked.

How does this component work?

The products protect electronic components from various types of interference and are used in a variety of systems in your car. Key function The device is filtering - for example, in car audio. Without a capacitor, the music system will not work well: extraneous noise, noise and volume changes. All this is a consequence of voltage surges in the car's electrical network.

Capacitors are found in many parts of the car. They act as buffers between batteries and other electronic devices. Without such a product, it is impossible to function not only the acoustics, but also the contact mechanism in the ignition distributor.

In the photo: diagram of the battery ignition system with digital designation of components:

1. Battery.
2. Starter switch.
3. Ignition switch.
4. Primary winding.
5. Secondary winding.
6. Ignition coil.
7. Distributor.
8. Breaker.
9. Capacitor.
10. Spark plug.

Types of Automotive Capacitors

How to understand that a device needs diagnostics

Various signs indicate a faulty capacitor. Headlights that flash in time with the bass of the car speakers mean that the car's electronic components are not receiving enough voltage. In some cases, the signals begin to become distorted, and individual components of the machine do not work correctly.

The ignition capacitor is responsible for producing a spark that ignites the air-fuel mixture in the engine cylinder. If the spark has a weak red color and appears unevenly, if the car cannot be started normally, it is likely that there are problems with the capacitor.

It is important to avoid problems with the ignition capacitor. They arise for three reasons:

• if the product has lost part of its capacity,
• if an internal break occurs,
• if a short circuit occurs.

The first two options are especially insidious, since the ignition does not immediately fail. The components continue to function, although the spark may no longer have the required power level. The main signs of a breakdown in such a situation are instability of engine operation at idling, problems with starting. Be sure to check the capacitor and replace it if necessary! If this is not done, sparks from the breaker will cause the contacts to burn, which will lead to power unit out of order.

How to check functionality

A reliable way to identify a fault is to use an ohmmeter or multimeter in ohmmeter mode. For the most complete testing, prepare the following tools:

• the measuring device itself;
• portable lamp;
• crank handle.

The main check is performed in the following sequence.

1. We switch the ohmmeter to the upper measurement limit mode.
2. We connect one terminal of the capacitor to the housing for discharge. We connect one of the ohmmeter probes to the tip of the wire, the other to the body.
3. If the indicator quickly deviates to “zero” and then smoothly returns to “infinity” - everything is in order. When changing polarity, the indicator quickly approaches zero. If the value “infinity” is immediately displayed, replacement is required.

Instructions for checking a car capacitor on video

Checking without a multimeter

1. We disconnect the wires coming from the capacitor and the ignition coil from the breaker. This is where a portable lamp comes in handy. To test the product, connect it to the interrupt terminal, then activate the ignition. Has the lamp turned on? The capacitor is not working properly.
2. Another method of checking the performance of the product is to charge the ignition coil capacitor with high voltage current and then discharge it to the housing. If a spark appears between the ground and the capacitor wire and a characteristic click is heard, everything is in order. No reaction? This means there is a breakdown in the capacitor.
3. Disconnect the black wire from the breaker terminal that comes from the ignition coil. Disconnect the capacitor wires from the breaker. Turn on the ignition and touch one wire to the other. If there is a spark, something is wrong. Most likely it is a breakdown of the capacitor.
4. Using the crank handle, turn the engine crankshaft and remove the cover from the ignition distributor. Turn on the ignition. You can evaluate the performance of the capacitor by monitoring the sparks that occur here. If a breakdown occurs, the breaker contacts will spark strongly. Another sign of a malfunction is weak sparking between the housing and the main high voltage wire.

The condition of the capacitor can be easily checked even on the road. Carry a multimeter with you and be prepared to use it - this way you will get rid of discomfort while driving and avoid the risk of serious damage.

The main malfunction of a capacitor in a contact ignition system is its breakdown to ground. In this case, the car engine may either fail at all or suddenly. Characteristic external signs malfunctions are: strong sparking between the contacts of the breaker when starting the engine and a very weak spark or its complete absence.

There are several ways to check the capacitor on VAZ 2105, 2107 cars.

— Using a control lamp.

We disconnect the wire coming from the ignition coil and the capacitor wire from the distributor (they are attached to one terminal “K” of the breaker). We connect between them control lamp, turn on the ignition and watch her. If it lights up, the capacitor is “broken” and must be replaced. No - OK.

— Using a wire from the ignition coil.

As in the method described above, we disconnect the wire from the coil and the capacitor wire from the terminal on the distributor. Turn on the ignition. We touch the tips of the wires. Sparking appears - the capacitor is faulty. No - everything is fine.

- Using a high voltage charge and subsequent discharge to ground.

We turn the crankshaft so that the breaker contacts in the distributor close. We disconnect only the capacitor wire from the distributor. Turn on the ignition. We bring the tip of the central capacitor to the tip of the capacitor wire high voltage wire from the ignition coil. Use a screwdriver to open the contacts of the breaker (or you can turn the distributor slightly by hand so that the contacts move apart). A spark will jump between the tip of the high-voltage wire and the tip of the capacitor wire - the capacitor will be charged with a high voltage current. We bring the tip of the capacitor wire to its body. The appearance of a discharge spark with a click indicates the normal condition of the capacitor. There is no spark - the capacitor is faulty.

Notes and additions

— Capacitor on VAZ 2105, 2107 cars and their modifications with contact system The ignition switch is installed on the distributor (30.3706-01) parallel to the breaker contacts and serves to increase the secondary voltage and prevent burnout of the contacts. It is charged when the contacts are opened and discharged through the secondary winding of the ignition coil, which causes an increase in the secondary voltage.

— Operating parameters of the capacitor of VAZ 2105, 2107 cars: the capacitance of the capacitor is measured in the frequency range 50 - 1000 Hz and is in the range of 0.20-0.25 μF, the insulation resistance at a temperature of (100±2)ºС and a DC voltage of 100 V should be more than 1 MΩ/μF.