The main conditions for the ignition of the mixture are the excess of the high (secondary) voltage over the breakdown voltage and the sufficiency of the spark discharge energy released in the spark gap of the spark plug. The spark discharge has capacitive and inductive phases. The duration of the capacitive phase is short and amounts to 1–3 μs. Therefore, the energy released in this phase of the spark discharge ensures the ignition of only a homogeneous and completely gasified working mixture. At start cold engine, when the vapor part of the fuel in the mixture is not enough, and its temperature is low, in addition to the capacitive phase of the discharge, an inductive one is required to ignite the working mixture. The duration of the inductive phase of the spark discharge is significantly longer than the capacitive one, which improves the heating of the mixture and its evaporation. This provides a better ignition of the mixture, which in its composition is near the flammability limits.

For ignition systems designed for engines with E > 9, the spark discharge energy reaches 0.05 J, and the duration is 2.5 ms. In this case, the increase in the secondary voltage over the breakdown voltage, characterized by a safety factor, is 1.4-1.5.

The magnitude of the breakdown voltage when starting the engine (especially cold) is always greater than in its operating modes. This is due to the low temperature of the spark plug electrode and the working mixture in the cylinder. The breakdown voltage depends on the compression pressure at the moment of breakdown of the spark gap and the distance between the spark plug electrodes. The breakdown voltage value is affected by the shape of the spark plug electrodes (the result of electrical erosion), with a change in which it increases by 3-4 kV for the first 25 thousand km of the car run.

The amount of secondary voltage developed by the ignition system depends on design and operational factors.

At starting speeds crankshaft engine, the time of the closed state of the breaker contacts is large enough, and the current strength in the primary circuit reaches its maximum value. With a low frequency of contact opening and a high breaking current induced in the primary winding of the coil, a breakdown of the spark air gap between the contacts is possible, which causes a deterioration in the parameters of the spark discharge.

The secondary voltage decreases as the voltage at the terminals decreases. battery, which is due to the low temperature of the battery and the degree of its discharge. To compensate for the decrease in voltage in the primary electrical circuit of ignition systems in domestic cars an additional resistor is introduced, short-circuited at the moment the starter is turned on.

It is necessary to note the influence of the non-uniformity of the electric starter cranking of the crankshaft on the reduction of the secondary voltage of the ignition systems. The secondary voltage drops during uneven crankshaft cranking by 0.2-1.5 kV compared to uniform cranking. A decrease in the secondary voltage is also possible with an increase in the shunt resistance and the gap between the electrodes. Shunting of candles when starting the engine occurs as a result of the re-enrichment of the mixture and the ingress of moisture and residues of combustion products between the electrodes. The greatest shunting of candles is observed in rotary piston engines (due to design features candle location) and two-stroke engines due to poor organization of the mixture formation process and poor cleaning of cylinders from residual gases. It is possible to increase the energy of the spark discharge and the magnitude of the secondary voltage in ignition systems only by increasing the breaking current of the primary electrical circuit of the ignition coil. In classical electromechanical systems, this possibility is limited by the service life of the breaker contacts. The highest operational reliability of the contacts occurs at a current strength of 1 A.

The problem of increasing the secondary voltage and energy of the spark discharge due to an increase in the breaking current of the primary circuit is solved using circuits of contact-transistor and non-contact ignition systems.

They provide easier conditions for the operation of the breaker contacts while increasing the breaking current of the primary circuit.

The secondary voltage developed by the contact transistor ignition system of the ZIL-508.1000400 engine is 25 kV, which provides a safety factor of 1.7-1.8 (1.35 for the classical system). The current strength in the primary circuit of the ignition coil is about 7 A and that interrupted by the breaker contacts is 0.7-0.9 A. positive quality the contact-transistor system is an increase in comparison with the classical duration and energy of the spark discharge (energy up to 0.024-0.025 J and duration up to 2.0-2.3 ms). The disadvantages of these systems include the influence on their characteristics of the voltage in the primary circuit and l, although it is somewhat less than that of the classical system.

The best systems in terms of starting are electronic non-contact systems with electronic or electromechanical automatic machines. ignition timing having non-contact control of the moment of ignition with a normalized time of energy accumulation in a magnetic field. In such systems, the energy accumulation time is almost independent of n, which improves the conditions for starting the engine. The energy of the inductive phase in the starting modes of the engine for domestic electronic systems (non-contact and microprocessor) is from 0.03 to 0.05 J, and the duration of the discharge is from 2.0 to 1.7 ms.

Electronic systems with energy storage in the electrostatic field of a capacitor and a switching element (thyristor) are widely used. A sharp increase in the secondary voltage provides low sensitivity to spark plug shunting. This nature of the increase in the voltage of the thyristor system, despite the short duration of the inductive component, makes it possible to increase the ignition reliability of fuel-oil mixtures of two-stroke and rotary-piston engines, as well as gas-air mixtures of gas engines.

Two-stroke starting engines are equipped with magneto ignition systems, which feature lower secondary voltage and spark discharge energy compared to a battery ignition system, especially in the range of crankshaft starting speeds of 200-300 min-1. To increase the safety factor for the secondary voltage, it is necessary to increase the starting speed of the crankshaft, which worsens the economic performance of the starting system.

The uneven rotation of the crankshaft of starting engines during electric start (5 reaches 1.85-1.90) leads to a decrease in the secondary voltage by 0.3-4.5 kV. This must be taken into account when choosing the parameters of magneto ignition systems.

It is possible to improve the start of starting engines through the use of electronic ignition systems, the minimum frequency of stable sparking of which should be no more than 100-150 min.

To ensure ignition combustible mixture in petrol cylinders power plant, an external source is used - an electric spark that jumps between the electrodes of the glow plug. But between these electrodes there is a certain gap, which the electrical voltage must break through. Therefore, a voltage of a large value, amounting to tens of thousands of volts, must be applied to the candle.

Classic ignition coil

Naturally, the car's on-board network is not only not designed, it is not even capable of delivering such a voltage, since there is no portable power source with such output parameters.

This problem was solved by including a special coil in the ignition system that generates high voltage. In fact, the ignition coil is a device that converts a low voltage (6-12 V) into high values ​​(up to 35,000 V).

This is the main function of this element - the generation of a high voltage pulse supplied to the incandescent.

The generation of voltage of significant readings by the design is achieved. The ignition coil is arranged simply, it consists of two types of windings.

Ignition coil design

Ignition coil device

The primary winding, which is also low-voltage, receives voltage supplied from the battery or. It consists of coils of large-section wire made of copper. Because of this, the number of turns of this winding is insignificant - up to 150 turns. To prevent possible voltage surges and the occurrence of a short circuit, this wire is covered with an insulating layer on top. The ends of this winding are brought out to the coil cover, and wiring with a voltage of 12 V is connected to them.

The secondary winding is placed inside the primary. It consists of a fine-section wire, which provides a large number of turns - up to 30,000. One of the ends of this winding is connected to the negative terminal of the first winding. The second terminal, which is positive, is connected to the center terminal of the coil. From this output, high voltage is supplied further.

The principle of operation of the ignition coil

The ignition coil works according to this principle: the voltage supplied from the power source passes through the turns of the primary winding, which creates a magnetic field that acts on the secondary winding. Due to this field, a high voltage pulse is formed in it. This value is affected by a large number of turns of a given winding, since the magnetic field induction of the first winding is multiplied by the number of turns of the secondary winding. Hence the high output voltage.

To increase the magnetic field inside the coil, thereby providing a higher output voltage, an iron core is placed inside the coil.

Video: Individual ignition coil VAZ

Something else useful for you:

Since current heating of the windings is possible during the operation of the coil, transformer oil is used for cooling, which fills the housing cavity. Its cover is sealed to the body, so the coil is non-separable. In the event of a malfunction, it is also not subject to repair.

The input and output voltage of the coil are not the main characteristics with which you can check its serviceability. The performance of the coil is checked by the resistance of its coil. In this case, each of the coils may have a different resistance. For example, the coil may have a resistance of the first winding at the level of 3.0 ohms, and the secondary - 7000-9000 ohms. Deviation during measurement from these values ​​will indicate a coil malfunction. And since it is not repairable, it is simply replaced.

The design of the coil has been described above. general type. It is installed on all cars that have a battery, contactless and electronic ignition system, and are equipped with a distributor that sends an impulse from the coil to the desired cylinder.

Dual Lead Coil

There are two more types of coils - two-pin and individual. Two-terminal coils are used in an electronic ignition system with a direct spark supply to the candle.

Dual coil. Very often used on motorcycles with an electronic ignition system. A feature is the presence of two high-voltage outputs. They can simultaneously receive a spark from two cylinders.

Its internal design practically does not differ from the coil of the general type. But such a coil has two conclusions for applying an impulse. That is, when the coil is operating, an impulse is applied to two candles at once. Since during the operation of the power plant at the same time the end of the compression stroke in two cylinders cannot be, but only in one cylinder, then in the second spark discharge that slips between the spark plug electrodes will not carry any useful function - an idle spark. But with the further operation of the engine, the situation will change - in the second cylinder there will be an end of the compression stroke and a spark is needed, and in the first cylinder it will be idle.

A two-terminal coil may have different ways connections to glow plugs. One way is to supply impulses through two high voltage wires. The second is the use of one tip and one high-voltage wire.

Such a coil allows you to do without a distributor, but it can only supply a spark to two cylinders. And usually a car uses 4 cylinders. For such cars, a four-pin coil is used, which in itself is two two-pin coils combined into one block.

Individual ignition coil

Depending on the device of the core, individual ignition coils are divided into two types - compact and rod
Compact (left) and rod (right) individual ignition coils mounted directly above the spark plugs.

The last type of coils used on cars are individual ones. Such coils work with only one, but when they are used, one of the elements, a high-voltage wire, is excluded from the spark-transmitting circuit, since the coil is placed.

It has a slightly different design, but the principle of operation has remained unchanged.

Individual ignition coil device

It has two cores. Two windings are located on top of the inner one. But in this coil, the secondary winding is located on top of the primary. The outer core is located on top of the windings.

The outputs of the secondary winding are connected to the tip, which is put on the candle. This tip consists of a high voltage rod, a spring and an insulator.

To protect the windings from significant loads, a diode is connected to the secondary, designed to work with significant voltage.

This design of the coil is very compact, which makes it possible to use one element per cylinder. And the absence of a number of other elements used in systems that are equipped with the first two types of coils can significantly reduce voltage losses in the circuit.

This and all currently produced ignition coils that are equipped with cars.

The ignition system ensures the operation of the engine and is integral part"Electrical equipment of the car".

The ignition system is designed to create a high voltage current and distribute it to the candles of the cylinders. A high-voltage current pulse is applied to the spark plugs at a strictly defined point in time, which varies depending on the crankshaft speed and engine load. Currently, cars can be installed contact system ignition or contactless electronic system.

Contact ignition system.

Electric current sources (battery and generator) generate low voltage current. They "give out" 12 - 14 volts to the on-board electrical network of the car. For a spark to occur between the electrodes of a candle, 18 - 20 thousand volts must be applied to them! Therefore, there are two electrical circuits in the ignition system - low and high voltages. (Fig. 1)

Contact ignition system(Fig. 2) consists of:
. ignition coils,
. low voltage circuit breaker,
. high voltage distributor
. vacuum and centrifugal ignition timing regulators,
. spark plugs,
. low and high voltage wires,
. ignition switch.

Ignition coil designed to convert low voltage current into high voltage current. Like most ignition system devices, it is located in engine compartment car. The principle of operation of the ignition coil is very simple. When an electric current flows through a low voltage winding, a magnetic field is created around it. If the current in this winding is interrupted, then the vanishing magnetic field induces a current in another winding (high voltage).

Due to the difference in the number of turns of the coil windings, from 12 volts we get the 20 thousand volts we need! This is just the voltage that is able to break through the air space (about a millimeter) between the electrodes spark plug.

Low voltage circuit breaker- is needed in order to open the current in a low voltage circuit. It is in this case that a high voltage current is induced in the secondary winding of the ignition coil, which then flows to the central contact distributor.
The breaker contacts are located under the cover of the ignition distributor. The leaf spring of the moving contact constantly presses it against the fixed contact. They open only for a short time, when the incoming cam of the drive roller of the breaker-distributor presses on the hammer of the movable contact.

Parallel contacts included capacitor. It is necessary so that the contacts do not burn at the moment of opening. During the separation of the movable contact from the fixed one, a powerful spark wants to slip between them, but the capacitor absorbs most of the electrical discharge into itself and the sparking is reduced to negligible. The capacitor is also involved in increasing the voltage in the secondary winding of the ignition coil. When the breaker contacts are fully opened, the capacitor discharges, creating a reverse current in the low voltage circuit, and thereby hastening the disappearance of the magnetic field. And the faster this field disappears, the more current appears in the high voltage circuit.

The low voltage circuit breaker and the high voltage distributor are located in the water housing and are driven by the engine crankshaft (Fig. 3). Often, drivers call this unit briefly - "breaker-distributor" (or even shorter - "distributor").

Distributor cover and high voltage distributor (rotor)(Fig. 2 and 3) are designed to distribute high voltage current to the candles of the engine cylinders.
After a high voltage current has formed in the ignition coil, it enters (through a high-voltage wire) to the central contact of the distributor cap, and then through a spring-loaded contact coal to the rotor plate. During the rotation of the rotor, the current "jumps" from its plate, through a small air gap, to the side contacts of the cover. Further, through high-voltage wires, a high-voltage current pulse enters the spark plugs.
The side contacts of the distributor cap are numbered and connected (by high-voltage wires) to the cylinder candles in a strictly defined sequence.

Thus, the "order of operation of the cylinders" is established, which is expressed by a series of numbers. As a rule, for four-cylinder engines, the sequence is: 1 - 3 - 4 - 2. This means that after ignition of the working mixture in the first cylinder, the next ignition will occur in the third, then in the fourth and finally in the second cylinder. This order of operation of the cylinders is set to evenly distribute the load on the crankshaft of the engine.
The application of high voltage to the spark plug electrodes should occur at the end of the compression stroke, when the piston does not reach the top dead center of approximately 40 - 60, measured by the angle of rotation of the crankshaft. This angle is called the ignition advance angle.

The need to advance the moment of ignition of the combustible mixture is due to the fact that the piston moves in the cylinder at great speed. If the mixture is ignited a little later, then the expanding gases will not have time to do their main job, that is, to put pressure on the piston to the right extent. Although the combustible mixture burns out within 0.001 - 0.002 seconds, it must be ignited before the piston approaches top dead center. Then, at the beginning and middle of the stroke, the piston will experience the necessary gas pressure, and the engine will have the power that is required to move the car.
The initial ignition timing is set and corrected by turning the housing of the breaker-distributor. Thus, we choose the moment of opening the contacts of the breaker, bringing them closer or vice versa, moving away from the incoming cam of the drive roller of the breaker-distributor.
However, depending on the operating mode of the engine, the conditions for the process of combustion of the working mixture in the cylinders are constantly changing. Therefore, to ensure optimal conditions, it is necessary to constantly change the above angle (4 o- 6 o). This is provided by centrifugal and vacuum ignition timing controllers.

The centrifugal ignition timing controller is designed to change the moment of occurrence of a spark between the electrodes of the spark plugs, depending on the speed of rotation of the engine crankshaft. With an increase in the speed of the crankshaft of the engine, the pistons in the cylinders increase the speed of their reciprocating motion. At the same time, the combustion rate of the working mixture remains practically unchanged. This means that in order to ensure a normal working process in the cylinder, the mixture must be ignited a little earlier. To do this, the spark between the electrodes of the candle must slip earlier, and this is possible only if the breaker contacts open earlier too. This is what the centrifugal ignition timing controller should provide (Fig. 4).

The centrifugal ignition timing controller is located in the breaker-distributor housing (see Fig. 3 and 4). It consists of two flat metal weights, each of which is fixed at one of its ends to a base plate rigidly connected to the drive roller. The spikes of the weights enter the slots of the movable plate, on which the bushing of the breaker cams is fixed. The plate with the bushing has the ability to rotate at a small angle relative to the drive shaft of the breaker-distributor. As the number of revolutions of the crankshaft of the engine increases, the frequency of rotation of the breaker-distributor roller also increases. The weights, obeying the centrifugal force, diverge to the sides, and shift the bushing of the breaker cams "in separation" from the drive roller. That is, the incoming cam rotates at a certain angle in the direction of rotation towards the contact hammer. Accordingly, the contacts open earlier, the ignition timing increases. With a decrease in the speed of rotation of the drive roller, the centrifugal force decreases and, under the influence of the springs, the weights return to their place - the ignition timing decreases.

Vacuum ignition timing controller is designed to change the moment of occurrence of a spark between the electrodes of the spark plugs, depending on the load on the engine.
At the same engine speed, the position of the throttle valve (gas pedal) may be different. This means that a mixture of different composition will form in the cylinders. And the rate of combustion of the working mixture just depends on its composition.
At wide open throttle, the mixture burns faster, and it can and should be ignited later. That is, the ignition timing must be reduced. And vice versa, when throttle valve covered, the combustion rate of the working mixture drops, so the ignition timing must be increased.

The vacuum regulator (Fig. 6) is attached to the body of the breaker - distributor (Fig. 3). The body of the regulator is divided by a diaphragm into two volumes. One of them is connected to the atmosphere, and the other, through a connecting tube, with a cavity under the throttle valve. With the help of a rod, the diaphragm of the regulator is connected to a movable plate, on which the breaker contacts are located.
With an increase in the throttle opening angle (increase in engine load), the vacuum under it decreases. Then, under the influence of the spring, the diaphragm, through the rod, shifts the plate along with the contacts at a small angle away from the incoming cam of the interrupter. The contacts will open later - the ignition timing will decrease. And vice versa - the angle increases when you reduce the throttle, that is, cover the throttle. The vacuum under it increases, is transmitted to the diaphragm, and it, overcoming the resistance of the spring, pulls the plate with contacts towards itself. This means that the breaker cam will meet the contact hammer earlier and open them. Thus, we increased the ignition timing for a poorly burning working mixture.

Spark plug(Fig. 7) is necessary for the formation of a spark discharge and ignition of the working mixture in the combustion chamber of the engine. I hope you remember that the candle is installed in the head
cylinder. When a high-voltage current pulse from the distributor hits the spark plug, a spark jumps between its electrodes. It is this "spark" that ignites the working mixture and ensures the normal passage of the engine's working cycle.
High voltage wires serve to supply high voltage current from the ignition coil
to the distributor and from it to the spark plugs.

The main malfunctions of the contact ignition system.

No spark between spark plug electrodes due to a break or poor contact of wires in the low voltage circuit, burning of the breaker contacts or lack of gap between them,
"breakdown" of the capacitor. Also, there may be no spark if the ignition coil, distributor cap, rotor, high-voltage wires, or the spark plug itself are faulty.
To eliminate this malfunction, it is necessary to check the low and high voltage circuits in series. The gap in the contacts of the breaker should be adjusted, and the inoperative elements of the ignition system should be replaced.

The engine runs intermittently and/or does not develop full power due to a faulty spark plug, violation of the gap in the contacts of the breaker or between the electrodes
candles, damage to the rotor or distributor cap, as well as incorrect setting of the initial ignition timing.
To eliminate the malfunction, it is necessary to restore the normal gaps in the contacts of the breaker and between the electrodes of the candles, set the initial ignition timing to
in accordance with the manufacturer's recommendations, but defective parts should be replaced with new ones.

Electronic non-contact ignition system.

The advantage of an electronic non-contact ignition system is the ability to increase the voltage applied to the spark plug electrodes. This means that the ignition process of the working mixture is improved. This facilitates the start of a cold engine, increases the stability of its operation in all modes. And this is of particular importance during our harsh winter months.
An important fact is that when using an electronic contactless ignition system, the engine becomes more economical.
Like the non-contact system, there are low and high voltage circuits. High voltage circuits are practically the same. But in the low voltage circuit, the non-contact system, unlike its contact predecessor, uses electronic devices- commutator and distribution sensor (Hall sensor) (Fig. 8).

The electronic non-contact ignition system includes the following components:
. sources of electric current,
. ignition coil,
. sensor - distributor,
. switch,
. spark plug,
. high and low voltage wires,
. ignition switch.
There are no breaker contacts in the electronic ignition system, which means there is nothing
burn and there is nothing to regulate. The contact function in this case is performed by a contactless
Hall sensor, which sends control pulses to the electronic switch. A
the switch, in turn, controls the ignition coil, which converts the low current
voltage to high volts.

The main malfunctions of the electronic non-contact ignition system.

If the engine with an electronic non-contact ignition system “stalled” and does not want to start, then first of all it is worth checking ... the supply of gasoline. Perhaps, to your delight, this was the reason. If everything is in order with gasoline, but there is no spark on the candle, then you have two options for solving the problem.
The first option involves an attempt to test in practice the opinion that "electronics is the science of contacts." Open the hood and check, clean, twitch and push on
all the wires and wires that come to hand have their places. If somewhere there were unreliable electrical connections, then the engine will start. And if not, then there is still the second option.
To be able to implement the second option, you should be a thrifty driver. From the reserve of necessary things that you carry with you in the car, first of all you need to take a spare switch and replace the old one with it. As a rule, after this procedure, the engine comes to life. If he still does not want to start, then it makes sense, successively changing to new ones, to check the distributor cap, rotor, proximity sensor and ignition coil. In the process of this “changing” procedure, the engine will still start, and later at home, together with a specialist, you will be able to figure out which particular node failed and why.
From the experience of operating the car in our conditions, I can say that most of the problems that arise in the ignition system are related to the “cleanliness” of native roads. In winter, liquid "porridge" from
dirty snow and saline climbs into all the cracks and corrodes everything that is possible. And in summer, the ubiquitous dust, into which, in particular, the winter “salty porridge” turns, is clogged
deeper and very pernicious effect on all electrical connections.

Operation of the ignition system.

Since we already know that “electronics is the science of contacts”, it is first of all necessary to monitor the cleanliness and reliability of electrical connections. Therefore, when operating
car sometimes you have to strip the wire terminals and plug connectors. Periodically, the gap in the contacts of the breaker should be monitored (Fig. 19) and, if necessary, adjusted. If the gap in the contacts of the breaker is greater than the norm (0.35 - 0.45 mm), then the engine is unstable at high speed. If less - unstable operation at speed idle move. All this happens due to the fact that the disturbed gap changes the time of the closed state of the contacts. And this already affects the power of the spark that jumps between the electrodes of the candle, and at the very moment of its occurrence in the cylinder (ignition advance).
Unfortunately, the quality of our gasoline leaves much to be desired. Therefore, if today you fill your car with bad gas, next time it may be even worse.
Naturally, this cannot but affect the quality of the combustible mixture prepared by the carburetor and the process of its combustion in the cylinder. In such cases, in order for the engine to continue to perform its work without fail, it is necessary to adjust the ignition system to today's gasoline.
If the initial ignition timing does not correspond to the optimal one, then the following phenomena can be observed and felt.

Ignition advance angle too large (early ignition):
. Difficulty starting a cold engine
. “pops” in the carburetor (usually audible from under the hood when trying to start
engine),
. a loss engine power(the car pulls badly),
. fuel consumption,
. engine overheating (coolant temperature indicator actively tends to the red sector),
. increased content of harmful emissions in exhaust gases.

Ignition advance angle less than normal (late ignition):
. "shots" in the muffler,
. loss of engine power
. fuel consumption,
. engine overheating.

Spark plug, as mentioned earlier, this is a small and seemingly simple element of the ignition system. However, for normal engine operation, the gap between the spark plug electrodes must be specific and equal in the spark plugs of all cylinders. For contact ignition systems, the gap between the electrodes of the spark plug should be in the range of 0.5 - 0.6 mm, for contactless systems a little more - 0.7 - 0.9 mm. Remember those "terrible" conditions in which spark plugs work. Not every metal can withstand huge temperatures in an aggressive environment. Therefore, the electrodes of the candles burn and become covered with soot, which means that we again need to “roll up our sleeves”. With a fine-grained file or a special diamond plate, we clean the electrodes of the candle from soot. We adjust the gap by bending the side electrode of the spark plug. We screw it into place or throw it away, depending on the degree of burning of the electrodes. Every time you unscrew the spark plugs, pay attention to the color of their electrodes. If they are light brown, then the candle is working normally, if they are black, then the candle may not work at all.
Recently, silicone high-voltage wires have appeared on sale. When replacing old, failed wires, it makes sense to purchase silicone ones, since they do not “break through” high voltage current. But interruptions in the operation of the engine often occur due to the leakage of a high voltage current pulse through a high-voltage wire to the car's ground. Instead of breaking through the air barrier between the spark plug electrodes and igniting the working mixture, the electric current chooses the path of least resistance and "goes to the side."
Avoid opening the hood of your car when it is raining or snowing outside. After a wet shower, the engine may not start, as water, having fallen on electrical equipment,
forms conductive bridges. The same effect, but more aggravated, occurs among those who like to ride on deep puddles at high speed. As a result of "bathing", all the instruments and wires of the ignition system located under the hood are flooded with water, and the engine naturally stalls, since the high voltage current can no longer reach the spark plugs. Well, to resume the trip, now it is possible only after hot engine with its heat it will dry everything “electric” in the engine compartment.

Ignition system This is a set of all instruments and devices that ensure the appearance of an electric spark that ignites the air-fuel mixture in the cylinders of an internal combustion engine at the right time. This system is part of the overall electrical system

For forced ignition of the air-fuel mixture, which entered the cylinder of a gasoline engine, the energy of a spark of a high-voltage electric discharge that occurs between the electrodes of the spark plug is used. Ignition systems are designed to increase the voltage of a car battery to the value necessary for the occurrence of an electrical discharge and, at the required moment, apply this voltage to the appropriate spark plug. We summarize the main systems in a table and describe the operation of such systems.

Designation		Description
Patriotic	foreign
		Classical contact with a breaker-distributor
		Electronic with energy storage in the system and contact sensor.
		Non-contact transistorized with inductive sensor
		Non-contact transistor with energy storage in a container with a Hall sensor
		Contact transistor with energy storage in inductive.
		Non-contact transistorized with energy storage in inductance with inductive sensor
		Non-contact transistorized with energy storage in inductance with Hall sensor
		Static type electronic ignition system

In such systems, the sensor of primary impulses(rotation sensor) are the contacts of a mechanical interrupter located in the ignition distributor (distributor), which is mechanically connected to the engine crankshaft through gears. One revolution of the distributor shaft is carried out for two revolutions of the engine crankshaft. The electrical discharge is created by means of a mechanical interrupter driven by a motor. An ignition coil is used to generate high voltage. Depending on the method of opening the primary circuit of the ignition coil, through which a large current passes, there are classic battery ignition, transistor ignition and thyristor-capacitor ignition. In such systems, the role of a power relay is performed by breaker contacts, a transistor or a thyristor.

diagram of the simplest contact ignition system (KSZ). We will consider the ignition coil device separately, but now we recall that the coil is a transformer with two windings wound on a special core. First, the secondary winding is wound with a thin wire and a large number of turns, and the primary winding is wound on top of it with a thick wire and a small number of turns. When the contacts are closed, the primary current gradually increases and reaches the maximum value determined by the battery voltage and the ohmic resistance of the primary winding. The rising current of the primary winding meets the resistance of the emf. self-induction directed opposite to the battery voltage.

When the contacts are closed, a current flows through the primary winding and creates a magnetic field in it, which crosses the secondary winding and a high voltage current is induced in it. At the moment of opening the contacts of the breaker, both in the primary and in the secondary windings, an emf is induced. self-induction. According to the law of induction, the higher the secondary voltage, the faster the magnetic flux created by the current of the primary winding disappears, the greater the ratio of the number of turns, and the greater the primary current at the moment of rupture.

To increase the secondary voltage and reduce the burning of the breaker contacts, a capacitor is connected in parallel with the contacts.

At a certain value of the secondary voltage, an electrical discharge occurs between the electrodes of the spark plug. Due to the increase in current in the secondary circuit, the secondary voltage drops sharply to the so-called arc voltage, which supports the arc discharge. The arc voltage remains almost constant until the energy reserve becomes less than a certain minimum value. The average duration of battery ignition is 1.4 ms. This is usually sufficient to ignite the air-fuel mixture. After that, the arc disappears, and the residual energy is spent on maintaining damped voltage and current fluctuations. The duration of the arc discharge depends on the amount of stored energy, mixture composition, crankshaft speed, compression ratio, etc. With an increase in crankshaft speed, the time of the closed state of the breaker contacts decreases and the primary current does not have time to increase to the maximum value. Because of this, the energy stored in the magnetic system of the ignition coil decreases and the secondary voltage decreases.

Negative properties of ignition systems with mechanical contacts appear at very low and high speeds of the yulenshaft. At low speeds, an arc discharge occurs between the breaker contacts, absorbing part of the energy, and at high speeds, the secondary voltage decreases due to the “bounce” of the breaker contacts. "Bounce" occurs when, when the contacts are closed, the movable contact hits the stationary one with the energy determined by the mass and speed of the movable contact, and then, after a slight elastic deformation of the contacting surfaces, it bounces, breaking the already closed circuit. After opening, the movable contact under the action of the spring again hits the fixed contact. Due to such a "bounce" of the contacts, the actual time of the closed state and, accordingly, the ignition energy and the value of the secondary voltage decrease.

Contact ignition systems ceased to cope with their functions with an increase in engine speed, the number of cylinders, and the use of poorer working mixtures. There was a need to use electronic ignition systems. The formation of the pricing moment can be carried out both by a conventional contact group (KTSZ), and using special sensors (non-contact systems).

Mechanical contacts only switch the control current of the base of the transistor, which is much less than the primary current flowing between emitter and collector. To protect a semiconductor device called a switch, it was necessary to reduce the value of the emf. self-induction in the primary circuit by reducing the inductance of the primary winding. The inductance of the primary winding decreases faster than its resistance. The emf decreases. self-induction and less prevents an increase in the primary current.

Due to the decrease in the inductance of the primary winding and the magnitude of the emf. self-induction to obtain a constant secondary voltage and increase the transformation ratio of the ignition coil.

Since the breaker contacts are energized only by the battery, the slight arc formed during opening makes it possible to do without a capacitor. Contacts are subject to mechanical wear and the possibility of "bounce" remains.

The difference between electronic ignition systems is that the switching and breaking of the current in the primary winding of the ignition coil is carried out not by closing and opening contacts, but by opening (conducting state) and locking (cutting off) a powerful output transistor. This allows you to increase the value of the break current up to 8 - 10 A, which allows you to increase the energy stored by the ignition coil by several times. Non-contact ignition systems use various types of sensors to signal. Below is a block diagram of the construction of ignition systems.

In the above ignition systems, the switch is located inside the engine ECU.

The above schemes of ignition control systems use a multi-coil construction. Coils can be individual, inserted into a spark plug tunnel (COP) with a switch built into the ECU engine. Sometimes one coil built into the candle tunnel serves two cylinders (an BB wire goes to the other candle). There are systems in which the switch is integrated into a single IGNITION MODULE, and such a module can be individual for a cylinder or a separate unit serving all cylinders. There are systems in which a single module is put on candles, which combines the ignition system and rotation and detonation sensors (SAAB, MERCEDES). Each system has its own advantages and disadvantages, and only the manufacturer decides which system or symbiosis of different systems to apply and create headache diagnosticians and car users.

diagnosing

The motor tester allows you to diagnose in detail the state of the high-voltage part of the system ignition by analyzing the waveform of the secondary voltage. The digital oscilloscope, which is the basis of a modern motor tester, is capable of displaying a real-time diagram of the high voltage of the ignition system. In addition, the firmware calculates ignition pulse parameters such as breakdown voltage, time and spark voltage. By learning to read oscillograms, you can understand what processes are taking place in the engine ignition system and quickly calculate the malfunction.

Electronic ignition systems(ESZ) have been successfully used for more than a decade. Their appearance made it possible to eliminate wear-prone mechanical part ignition system and, thereby, significantly increase its reliability. The absence of a distributor means the absence of such parts that are subject to regular replacement, such as the distributor cap and slider, as well as vacuum and mechanical components that require maintenance and often cause a lot of trouble to car owners. Summarizing the above, we can confidently state that the ESZ is many times more reliable than its predecessor containing a distributor.

But even despite the obvious advantages, the ESZ cannot be called absolutely trouble-free. System failures occur for a variety of reasons, and knowing how to correctly locate and diagnose system problems will help you quickly solve the problem of starting an engine or misfiring in one or more cylinders.

Failure to start the engine is possible for three reasons: lack of fuel supply, lack of ignition spark, or a decrease in compression in the cylinders. Of these three causes, the easiest to diagnose is the absence of a spark, since on most engines you can simply remove the high voltage spark plug wire and verify the presence or absence of a spark by starting the starter and holding this wire a short distance from any metal ground connected to the ground. In systems with a coil mounted directly on the spark plug (a separate article in our review is devoted to the KNS system), there are no high-voltage wires. In this case, it is enough to remove the coil from the candle and follow the procedure described above using an additional wire or a screwdriver.

Thus check up existence of a spark in each of cylinders. Its complete absence in all cylinders indicates the failure of the ESZ module or the crankshaft position sensor (DPK). Many engines equipped with an electronic fuel injection system also use DPK signals to synchronize the injector pulses. So if, in addition to the absence of a spark, there is a lack of fuel supply from the injector nozzles, the reason lies precisely in the failure of the WPC. The absence of a spark in one or two cylinders using a high-voltage pulse of the same coil of the ESZ block indicates the failure of the corresponding coil.

The working mixture in the engine cylinder ignites from an electric spark that jumps at the right time. To ensure timely ignition of the working mixture, an ignition system is designed, which can be of three types:

contact;
non-contact (transistor);
electronic.
We can say that the time of contact and non-contact systems is almost gone. V modern machines, as a rule, an electronic ignition system is used. However, given the fact that many of our compatriots drive Soviet and old Russian cars, briefly consider the principles of operation of contact and transistor ignition systems. The latter, in particular, is used on the VAZ-2108. Concerning electronic system ignition, then in practice there is no need to study it, since adjusting electronic ignition possible only at a specialized service station.

An electrical spark in a contact ignition system is formed between the spark plug electrodes at the end of the compression stroke. Since the gap of the compressed working mixture between the electrodes of the spark plug has a high electrical resistance, a large voltage must be created between them - up to 24,000 V: only in this case will a spark discharge be caused. By the way, spark discharges should appear at a certain position of the pistons in the cylinders and alternate in accordance with the established order of operation of the cylinders. In other words, the spark should not jump during the intake, compression or exhaust stroke.

The contact battery ignition system consists of the following elements:

sources of electric current (battery and generator);
ignition coils;
ignition lock (the driver inserts the key into it to start the car);
low voltage current interrupter;
high voltage current distributor;
condenser;
spark plugs (based on one cylinder - one candle);
electrical wires of low and high voltage.
Sources of electric current provide its supply to the ignition system. When starting the engine, the source is the battery. The running engine constantly receives recharging from the generator.

The main purpose of the ignition coil (it is located in the engine compartment) is to convert low voltage current into high voltage current. When an electric current passes through a low voltage primary winding, a powerful magnetic field is created around it. After the current supply is stopped (this task is performed by an interrupter), the magnetic field disappears and crosses a large number of turns of the high voltage secondary winding, as a result of which a high voltage current appears in it. A significant increase in voltage (from 12 to the required 24,000 V) is achieved due to the difference in the number of turns in the coil windings.

The resulting voltage allows you to overcome the space between the electrodes of the spark plug and get an electrical discharge, as a result of which the required spark is formed.

Note: The average gap between the spark plug electrodes is 0.5-1 mm. If necessary, it can be adjusted by unscrewing the candle.

If the gap between the electrodes of the spark plug is not adjusted, the engine is unstable: not all cylinders may function. For example, out of 4 cylinders, 3 work, another 1 is spinning “idle” (in such cases, they say that the motor is troit). In this case, the engine noticeably loses power, and fuel consumption increases.

By adjusting the gap between the electrodes of the candle, only the side electrode is bent. It is forbidden to bend the central electrode, as this may cause cracks on the ceramic insulator of the candle and it will become unusable.

The functions of the ignition lock are known even to beginners: it is necessary to close the electrical circuit and start the car.

The task of the low voltage breaker is to interrupt the supply of low voltage current to the primary winding of the ignition coil in time, so that at that moment a high voltage current is formed in the secondary winding. The resulting current is fed to the central contact of the high voltage current distributor.

The breaker contacts are located under the cover of the ignition distributor. The moving contact is constantly pressed against the fixed contact by means of a special leaf spring. These contacts open for a very short period of time at the moment when the incoming cam of the distributor drive roller presses on the hammer of the moving contact.

To prevent the contacts from failing prematurely, a capacitor is used that protects the contacts from burning. The fact is that at the moment of opening the movable and fixed contacts, a powerful spark could jump between them, but the capacitor absorbs almost the entire electrical discharge.

Another task of the capacitor is to help increase the voltage in the secondary winding of the ignition coil. When the movable and fixed contacts of the breaker open, the capacitor discharges and creates a reverse current in the low voltage coil, which accelerates the disappearance of the magnetic field. In accordance with the laws of physics, the faster the magnetic field disappears in the primary winding, the more powerful the current appears in the secondary winding.

This function of the capacitor is extremely important. After all, if it is faulty, the car engine may not work at all, since the voltage that occurs in the secondary winding will not be enough to break through the gap between the spark plug electrodes and, therefore, to produce a spark.

The low voltage current interrupter and the high voltage current distributor are combined in one housing and represent a device called a distributor. Its main elements:

cover with contacts;
thrust;
housing of the vacuum regulator;
vacuum regulator diaphragm;
distributor rotor (runner);
base plate;
resistor;
contact coal;
centrifugal regulator with plate;
interrupter cam;
movable breaker plate;
weight;
contact Group;
drive roller.
With the help of a rotor and a cover, the high voltage current formed in the ignition coil is distributed to the engine cylinders (more precisely, to the candles in each cylinder). Further, the current through the high-voltage wire is supplied to the central contact of the distributor cover, and then through the spring-loaded contact coal to the rotor (runner) plate. The rotor rotates, and the current passes through a small air space to the side contacts of the distributor cover. High-voltage wires are connected to these contacts, which conduct current to the spark plugs. Moreover, the wires with the contacts are connected in a strictly defined sequence, with the help of which the order of operation of the internal combustion engine cylinders is established.

In most cases, the sequence of operation of 4-cylinder engines is as follows: first, the working mixture ignites in the first cylinder, then in the third, then in the fourth, and finally in the second. In this order, the load on the crankshaft is distributed evenly.

The high voltage current should not flow to the spark plug at the moment when the piston has reached top dead center, but a little earlier. The pistons in the cylinders move with high speed, and if a spark appears at the moment the piston is in the upper state, the burnt working mixture will not have time to exert the necessary pressure on it, which will lead to a noticeable loss of engine power. If the mixture ignites a little earlier, the piston will experience greatest pressure, therefore - the engine will show maximum power.

When exactly should the spark appear? This parameter is called the ignition timing: the piston does not reach approximately 40-60 ° to the top dead center, if measured by the angle of rotation of the crankshaft.

To adjust the initial ignition timing, the distributor housing is rotated until it is found best option. In this case, the moment of opening the movable and fixed contacts of the breaker is chosen when they either approach or move away from the incoming cam of the distributor drive roller. By the way, the distributor is driven by the crankshaft of the engine.

In different engine operating modes, the combustion conditions of the working mixture change, so the ignition timing needs to be constantly adjusted. Two devices help to solve this problem: centrifugal and vacuum ignition timing controllers.

The centrifugal ignition timing controller consists of two weights on axles mounted on a drive roller plate. The weights are pulled together by two springs. In addition, they have pins that are inserted into the slots of the breaker cam plate. The main purpose of the centrifugal ignition timing controller is to change the moment the spark appears between the spark plug electrodes, depending on the speed at which the engine crankshaft rotates.

As the crankshaft speed increases, the weights under the action of centrifugal force diverge to the sides and turn the plate with the breaker cam in the direction of its rotation by a certain angle, which ensures earlier opening of the breaker contacts. Therefore, the ignition advance is increased.

As the crankshaft speed decreases, the centrifugal force also decreases. Under the action of the coupling springs, the weights converge, turning the plate with the breaker cam in the opposite direction. The result is a reduction in ignition timing.

A vacuum regulator is designed to automatically change the ignition timing depending on the current load on the engine. As you know, depending on the state of the throttle valve, a mixture of different composition enters the engine cylinders, respectively, its combustion takes a different time.

The vacuum regulator is mounted in the distributor, and the regulator body is divided by a diaphragm into two cavities, one of which communicates with the atmosphere, the other through a tube with a carburetor (more precisely, with a throttle space). When the throttle valve is closed, the vacuum in the vacuum regulator increases, the diaphragm, overcoming the resistance of the return spring, bends outward and, through a special rod, turns the movable disk towards the rotation of the breaker cam in the direction of increasing the ignition timing. When the throttle valve opens, the vacuum in the cavity decreases, the diaphragm under the influence of the spring bends in the opposite direction, turning the breaker disk in the direction of rotation of the cam in the direction of decreasing the ignition timing.

On the old Soviet and Russian cars you can manually adjust the ignition using an octane corrector.

A key element of the car's ignition system is the spark plug. Whatever car you drive - Mercedes, Zhiguli, Lexus or Zaporozhets - you cannot do without candles. Recall that the number of candles corresponds to the number of engine cylinders.

When a high voltage current enters the spark plug from the distributor, an electrical discharge jumps between its electrodes, igniting the working mixture in the cylinder. During combustion, the working mixture presses on the piston, which, under pressure, moves down and scrolls the crankshaft, from which the torque is transmitted to the driving wheels of the car.

As for the non-contact (transistor) ignition system, its main advantage lies in the possibility of increasing the voltage power supplied to the spark plug electrodes. This greatly simplifies the launch cold engine, as well as his work in the cold season. In addition, a car with a contactless ignition system is more economical.

The main elements of a contactless ignition system are:

sources of electric current (battery and generator);
ignition coil;
spark plug;
distribution sensor;
switch;
ignition switch;
high and low voltage wires.
A characteristic feature of the transistor system is that it does not have interrupter contacts, instead of which a special sensor is used. It sends pulses to the switch that controls the ignition coil. The ignition coil, as usual, converts the low voltage current into a high voltage current.

Among the most common malfunctions of the car ignition system, first of all, it should be noted late or early ignition, interruptions in one or more cylinders, as well as a complete lack of ignition.

If you notice that the engine is losing power and overheating at the same time, late ignition may be to blame. When the loss of power is accompanied by a characteristic knock in the engine, it is most likely an early ignition. In any case, to solve the problem, it is necessary to adjust the ignition timing (as motorists say, set the ignition). V modern cars It is almost impossible to do this on your own, so immediately contact a service station.

If a cylinder is intermittent (motor troit) - first of all, check the condition of the spark plug: it is possible that carbon deposits have formed on its electrodes, which must be removed or the gap between the electrodes adjusted. In addition, the cause of the failure of the candle is the presence of cracks and other mechanical damage on the ceramic insulator.

Note: The spark plug is one of those parts that rarely needs to be replaced. On average, a spark plug can "pass" several tens of thousands of kilometers, so the cause of such problems is not necessarily a malfunction of the candles.

Even an inexperienced motorist can replace spark plugs. To do this, it is necessary to disconnect high-voltage wires from them, then with a special candle wrench unscrew the old spark plugs and screw in the new ones. The operation is simple, it takes literally 10-20 minutes.

Sometimes it is difficult to determine by eye which candle is faulty (that is, which cylinder is intermittent). To find damage, disconnect the high-voltage wires from the corresponding candles one by one by removing their tips: if interruptions in engine operation become more noticeable, this candle is in good condition, and if engine operation has not changed, it means that it is out of order. An additional confirmation of the malfunction of the candle may be that it will be colder than the others after unscrewing it from a hot engine.

There are damages to the high-voltage wire, as a result of which electricity is supplied intermittently or not supplied at all. It is recommended to check the condition of the contact by which the wire is connected to the candle: it happens that in order to eliminate the malfunction, it is enough to press it more tightly. In older machines with a contact ignition system, the problem may be in the corresponding socket of the breaker-distributor cover.

If there are interruptions in the operation of different cylinders, check the condition of the central high-voltage wire: there is a possibility of damage to the insulation. Perhaps this is due to a failed capacitor, poor contact of the high-voltage wire with the ignition coil terminal or the socket of the breaker-distributor cover (in machines with a contact ignition system). In older cars, the reasons may be the burning of the breaker contacts, the periodic short to ground of the movable contact of the breaker due to damaged insulation, the appearance of cracks on the cover of the distributor, the unadjusted gap between the breaker contacts.

Spark problems are solved by treating the ignition distributor and high-voltage wires with a water-displacing aerosol. Such aerosols in assortment are sold on automotive markets and in specialized stores. In particular, VD-40 aerosol is popular among domestic motorists.

A rather unpleasant symptom is the complete absence of ignition. As a rule, the reason lies in the malfunctions of high-voltage or low-voltage circuits. To eliminate them, you will have to contact a service station.

Attention: In the case of independent work on maintenance and repair of the ignition system with the engine running, do not touch the elements of the ignition system with your hands, and also do not check their performance “for a spark”. When the ignition is on, the plug connector must not be disconnected from the switch, as this can lead to failure of the capacitor. It is forbidden to lay high-voltage and low-voltage wires in the same bundle.