Ignition system. Contact ignition system: circuit, principle of operation

The engine ignition system is needed to reproduce the currents of increased value and distribute it to the contact spark plugs of the fuel. Given the change in engine speed and load on the motor, a high voltage voltage pulse is applied to the candles in a given period. Nowadays, cars are equipped with contact and non-contact systems of the moment of ignition.

The device of contact system of ignition

Low-voltage currents serve as a power source and come from the generator and the car battery.

Typically, the value of this voltage is equal to twelve to fourteen volts. And for the reproduction of the moment of the spark in the candles of the fuse, it is necessary to feed them up to twenty thousand volts. Given this factor, the ignition system has in its design two different electrical circuits. The circuit of the ignition system is assembled from the following devices and elements: battery, coil, trambler, ignition timing advisors of vacuum and centrifugal types, contact candles, electric wires, lock switch.

Individual elements of the system

To convert low-voltage currents to high voltages, the installation of an ignition coil device is provided . It is located in the hood space, as well as most of the elements and mechanisms of ignition. The main way of working is the following: on the windings of the windings of not high voltage pass electrical currents, and at that moment a magnetic field is converted around the winding. In the event that you stop supplying voltage in the turns, the missing magnetic field excites the currents already directly in the high voltage turns. The process of converting twelve volts into twenty thousand is due to the difference in turns in the windings of the coils. It is this high voltage that is needed to create a spark between the candle contacts.

Operation of the breaker

The correct operation of the ignition system is impossible without such a mechanism as a breaker of current voltages of not high values. His job is to interrupt the currents in the low voltage windings. This, in turn, contributes to the formation of high voltage.

Then the current is directed to the main contact located under the cover of the distributor device. The flexible spring of the movable contact keeps it pressed against the fixed element all the time, and they diverge only for a short time. This occurs at the moment when the cam of the drive mechanism of the chopper mechanism acts on the hammer of the movable contact.

Capacitor

To exclude the fact of ignition of contacts at the time of their opening, a capacitor is connected in parallel to them. In the period of divergence of the contacts of the distributor mechanism between the cams, sparking is possible. In this case, the capacitor serves to absorb most of the electric power and reduces the possibility of the formation of a spark to a minimum. In addition, it accompanies an increase in the voltage in the secondary coil windings of the coil. At the moment the breaker contacts trip, the condenser releases its current and thus creates reverse currents in the low voltage circuit. This helps to accelerate the disappearance of magnetic fields. And the sooner this happens, the higher the currents in the high voltage line. In the event that the capacitor of the trambler fails, the motor will also not start and run. The voltage parameters of the secondary circuit turns will be too small for optimum sparking. The spark between the candle electrodes will be "poor", and this is not enough to ignite the fuel mixture. The contacts of the low-current breaker and the high-voltage distributor are installed in the casing of the trampler and are activated by the crankshaft of the motor.

Tray cover

The distribution of high voltage on the spark plugs of the power unit cylinders is carried out by means of the distributor cover of the trambler. After the formation of high currents in the coil, they enter the main contact of the cap of the distributor-interrupter, and only then, through the movable element, onto the rotor plate. At the time when the rotor rotates, the voltage jumps from the plate to the contacts of the distribution cover.

Then, short pulses through high voltage boprovopods come directly to the spark plugs. The contacts of the distribution cover have a certain numerology, which corresponds to a certain cylinder of the engine.

This is precisely how the cylinder operates. A certain work order provides for an even load distribution to the crankshaft. Basically, four-cylinder motors have the following order of operation: 1-3-4-2. But it can vary insignificantly depending on the manufacturer. In this case, the work order formula means that initially the ignition occurs in the first cylinder, then in the third, fourth and second. In this case, the engine ignition system provides for supply of voltage to the candles at the end of the compression stroke. This is due to the setting of the ignition timing.

An advance in the moment of sparking is necessary because of the high speed of displacement of the pistons in the cylinders. In the event that the fuel mixture will ignite a little later or earlier than envisaged, the efficiency of the expanding gases will significantly decrease. Therefore, the ignition of the fuel must be carried out at a given moment, when the piston is approaching the TDC. With the correct angle of advance, the piston will be affected by the optimum amount of gases necessary for the normal operation of the engine. The advance angle is set by turning the chopper housing. So a certain moment is selected, when the contacts of the breaker are getting divorced.

The centrifugal regulator

The centrifugal regulator ensures that the correct ignition timing is set depending on the engine speed. The design of the mechanism of the regulator is a pair of loads that rotate, act on the plate with the contacts of the interrupter.

Vacuum regulator

Depending on the degree of load on the engine, the instant of spark formation is corrected by a vacuum regulator. This device is mounted on the body of the trampler. The vacuum regulator consists of two chambers separated by a diaphragm. One chamber interacts with the atmosphere, and the other with a nozzle with a capacity of the throttle. With the help of the rod, the diaphragm has a connection to the plate, which is equipped with a breaker contacts.

With an increase in the angle of rotation of the throttle valve, there is a decrease in the discharge in the throttle cavity. In this case, the diaphragm moves the plate to a small angle together with the contacts towards the cam of the breaker drive. Proceeding from this, the opening occurs with a delay, and, accordingly, the angle changes.

Spark plugs (ignition system, contact)

The ignition system is equipped with standard fuse elements. Contact elements of sparking are needed to convert electrical energy into a spark, to ignite the fuel mixture in the engine cylinders. At a time when the electrical impulse is transferred to the candles, its contacts contribute to the formation of a spark breakdown. This part is an integral part of the ignition system.

Armoprovoda

The ignition system is contact, the ignition system of other types in its kit is equipped with armored cables that can pass high voltage through themselves without damage and loss. In particular, it is an electric flexible wire, with one copper core and multi-layer insulation.

In this case, the contact wire is made in the form of a spiral, which eliminates radio interference. As a rule, these wires are installed on candles. With prolonged use, the insulation of the wires can acquire microcracks, through which loss of impulses of high values is possible.

Ignition system malfunctions and their elimination

The first and most common breakdown may be the absence of a spark on candles. The following may serve as the reasons for this malfunction:

• Breakage of electric wires in the low voltage circuit or oxidation of their connecting contacts.
• The ignition of the distributor's contacts and their misalignment.
• Failure of the coil, the condenser burnout, the defects of the distributor cover, damage to the armored pipes and the candles themselves.
• Excessive moisture in the devices.

Troubleshooting is possible using the following method:

• Checking the entire circuit and wiring with a test and measuring device.
• Cleaning the trambler contacts from the deposit and adjusting the gap.
• Replacement of faulty and suspicious state of system parts.

It happens that when the ignition key turns, the starter does not work, and all systems work visually, in this case it is necessary to pay attention to the block of safety elements, since it is possible to burn out or oxidize the seat of the fuse responsible for starting the starter.

If the engine of the car is unstable and does not develop full power, the reasons may lie in the following:

• Failure of one of the spark plugs.
• Too large or, conversely, a small gap on the candles and contacts of the distributor.
• Mechanical damage to the rotor or cover of the trambler.
• Invalid advance angle set.

Repair consists in the following:

• Installation of new parts.
• Adjustment of the necessary clearances.
• Adjustment of the angle of sparking.

The scheme of the contact ignition system is quite simple and is widely used on various cars.

With the use of new technologies of ignition elements, cars are constantly being improved and modified. For example, newer models of machines from different manufacturers have long used electronic ignition systems. When problems occur in the system, you can easily determine the cause of their occurrence and repair. The contact ignition system of the car VAZ has no cardinal differences from the elements of other manufacturers and has a high operational reliability. It is inexpensive to repair.

Contact-transistor system

In comparison with the conventional contact system, the contact-transistor has in its equipment a transistor. Its application contributes to improved performance and performance. With the installation of the transistor, the system was equipped with a switchboard.

The device of the contact-transistor ignition system does not differ much from the usual ignition and its operating principle. But still it has some minor differences.

Its main distinguishing feature is the possibility of the impact of the interrupter on the device of the transistor, and not on the winding of the coil. During the interruption of the currents in the low-voltage winding in the windings of the high-voltage winding, its formation takes place.

The contact ignition system (VAZ including) has a number of positive characteristics.

Controlling the processes that are inherent in the ignition coil, contributes to the possibility of increasing the currents in the primary coil winding, and as a result, it is possible:

• Increase in secondary voltage.
• Increase the gaps between the electrodes of the candles.
• Improved and more stable moment of sparking.
• Make it easier to start the engine in the cold season.
• Increased engine speed and power.

Such a contact-transistor ignition system provides for the connection of a coil with a separate primary and secondary windings.

In this case, this system reduces the load on the contacts of the breaker and reduces the risk of their burning. This is possible because of the decrease in the indices of passing currents. Due to this fact, the reliability and longevity of the entire system is increased.

The disadvantages of such an ignition include the following: the voltage of the currents arriving at the transistor has a significant influence on its operation. The lowering of the indications of currents related to the state of the contacts of the breaker strongly affects the operational parameters of the contact-transistor ignition. The faults of the ignition system of this type are identical to those of the conventional contact system and are eliminated in the same way. But in addition, there may be problems with a malfunction of the transistor and the switch.

Engine start system

The engine can not be started without additional electronic devices. In this context, we are talking about a mechanism like a car starter. This mechanism is an electric motor that causes the crankshaft of the motor to move to the moment of ignition in the cylinders and starting the engine. In operation, the starter is turned on by turning the key in the lock to the appropriate position. The currents through the ignition relay come from the battery to the starter turns and activate it.

If we consider in detail, the process of starting the engine is carried out in three stages:

1. The retractor mechanism of the starter drives the starting gear into engagement with the flywheel crown.
2. Further, the starter rotor rotates together with the drive gear, and the latter, in turn, transfers the torque to the crankshaft, which leads to the launch of the power unit.
3. After the engine is started and the ignition key returns to its original position, the retracting mechanism drives the starter drive gear from meshing with the flywheel.

Purpose of the relay

Any electrical relay is a safety device that is equipped with an ignition system. The contact ignition system in this respect is also no exception. Its main purpose is to open and close various areas in the electrical circuits of the car. The devices differ in the design and method of the control signal, as well as in installation. At the moment, electromagnetic relays are widely used .

In simple words, this type of electrical equipment auto protects various elements from high current loads. Simply, it serves as a switch. In particular, in the ignition system, the relay protects the car starter and generator from the effects of high currents on them. For example, to start the engine you need to crank the ignition and turn on the starter in the work, which, in turn, consumes from 80 to 300A.

In this case, if you do not use the relay, the lock may burn, as well as some wiring elements. In order for this not to happen, the system includes an ignition relay. When there is a diode icon on the body of the device, it means that when connecting it, it is important to observe the polarities of the terminals. Otherwise, failure is unavoidable.

Conclusion

As a result, it is worth noting that the first, widely used in the automotive market, was a contact ignition system. This ignition system was used quite confidently, but at the moment it is considered morally obsolete. The weakest point of it was just the presence of a contact pair in the construction of the trambler. After all, it required periodic maintenance, reduced to the need for checking and adjusting the gap between contacts, cleaning the surface of contacts from various kinds of burn marks, which could significantly affect the performance of the elements as a whole. This system was replaced by contactless, which does not require such maintenance works and is characterized by motorists as more reliable.

So, we found out what kind of operation the contact-transistor ignition system of a car has.