The system of ignition creates in each cylinder of the engine, at some point, the spark category which ignites injectable fuel mix. For formation of a spark, in the ignition coil tension of the battery 12B will be transformed to the high voltage of ignition of 25 000-30 000 Century.

The system of ignition generally consists from: coils of ignition, spark plugs, the ignition distributor with Hall's sensor, the control unit of ignition of TCI-H (TSZ — H), FEl (VEZ), Digifant, KE-Motronic. 

Carburetor engines, as well as engines with system of injection of Mopo-Jetronic fuel, are supplied with transistor system of ignition TCI-H (TZS).

The DOCH engine without catalyst, with alphabetic reference of KR has transistor system of ignition in the form of the additional block. This system of ignition is called FEl (VEZ).

At engines with system of ignition and injection of Digifant developed by VW, FEl (VEZ) is built in the control unit of system of injection and supplied in addition with the detonation sensor.

In the KE-Motronic system of BOSCH installed on the engine of 2,0 l of DOCH with the catalyst is available, in comparison with the Digifant system, only the control unit of ignition and injection.

System of ignition TCI-H (TSZ — H)

Fig. 6.3. System of ignition TCI-H (TSZ — H): 1 – switchboard; 2 – high-voltage wires; 3 – tips of suppression of hindrances; 4 – screen; 5 – ignition distributor cover; 6 – coal contact; 7 – spark plug; 8 – spark plug tip; 9 – ignition coil; 10 – protective cover; 11 – the contact socket 1 (–); 12 – contact socket 15 (+); 13 – plug 4

Fig. 6.4. Hall's effect

The transistor system of ignition (fig. 6.3) is a contactless system of ignition. Instead of the breaker the distributor of ignition is supplied with Hall's sensor which is not demanding leaving. The condenser of ignition is absent. The sensor — contactless, microelectronic, is based on use of effect of Hall (fig. 6.4) . This effect consists in emergence of cross electric field in a semiconductor plate with current, at action on it magnetic field. The sensor consists (fig. 6.5) of a permanent magnet, a plate of the semiconductor and a chip. Between a plate and a magnet there is a gap. In a gap of the sensor there is a steel screen with cuts. When through a gap there passes the screen cut, the plate of the semiconductor is affected by magnetic field and from it the potential difference is removed. If in a gap there is a screen body, then magnetic power lines become isolated via the screen and do not affect a plate. In this case the potential difference on a plate does not arise. The separate electronic relay operates a chain of low voltage of the coil of ignition.

Fig. 6.5. The principle of operation of the sensor on use of effect of Hall: 1 – the steel screen with cuts; 2 – magnets; 3 – Hall's sensor; 4 – air gap; b — width of a petal of the steel screen

The corner of an advancing of ignition changes automatically, the spark of ignition occurs only in strictly certain depending on loading and turns of the engine. The advancing of ignition is run by the vacuum regulator of an advancing of ignition. Vacuum operates a diaphragm which one party is connected through a tube to an inlet collector. Discharge and other party — to the support plate. Depression in an inlet collector changes depending on turns of the engine and extent of opening of a butterfly valve, and forces a diaphragm to move. The diaphragm in turn moves the support plate, increasing or reducing a corner of an advancing of ignition and, as a result, changes the ignition moment.

System of ignition of FEl (VEZ)

Fig. 6.6. System of ignition of FEI (VEZ): 1 – electric socket; 2 – sensor switch of a butterfly valve; 3 – switchboard; 4 – control unit; 5 – vacuum шлан; 6 – electric socket; 7 – connection with "weight", 8 – connection with "mass" of the control unit; 9 – high-voltage wire; 10 – ignition distributor; 11 – distributor cover; 12 – interference eliminator cover; 13 – the plug 1 (–); 14 – plug 4; 15 – tips; 16 – plug 15 (+); 17 – connection with "mass" of the switchboard; 18 – ignition coil; 19 – coal contact; 20 – ignition distributor rotor; 21 – dustproof cap; 22 – temperature sensor; 23 – electric socket; 24 – sealing ring; 25 – bolt; 26 – sealing ring; 27 – spark plug; 28 – spark plug tip

It is transistor system of ignition with an electronic control unit (fig. 6.6) . The control unit of an electronic way corrects the ignition moment that in the TCI-H (TSZ — H) system is carried out thanks to centrifugal and vacuum regulators.

System of ignition and injection of Digifant

Fig. 6.7. System of ignition and injection of Digifant: 1 – control unit (switchboard); 2 – electric socket; 3 – assembly panel; 4 – nut; 5 – sensor switch of a butterfly valve; 6 – bolt; 7 – the detonation sensor (on the block of cylinders); 8 – sensor of temperature (blue); 9 – electric socket; 10 – Digifant control unit

In this system (fig. 6.7) electronic control by ignition and injection is joint in one control unit. System of ignition transistor with Hall's sensor and an electronic control unit defining the ignition moment. The device of system of ignition Digifant generally corresponds to system of ignition of FEl (VEZ), however, in addition the moment of ignition is corrected also on a detonation sensor signal which is sensitive to premature ignition and respectively reduces an ignition advancing corner.

System of ignition and injection of KE-Motronic

Fig. 6.8. System of ignition and injection of KE-Motronic: 1 – mending candle tip; 2 – sealing ring; 3 – a grounding plate on a head of the block of cylinders; 4 – case of a butterfly valve; 5 – bolt; 6 – dustproof cap; 7 – electric socket; 8 – distributor rotor; 9 – control unit; 10 – high-voltage wires; 11 – electric sockets; 12 – one-contact electric socket; 13 – protective cover; 14 – ignition coil; 15 – tips; 16 – the sensor on a high-voltage wire of the 4th cylinder; 17 – interference eliminator cover; 18 – a distributor cover, 19 – coal contact; 20 – ignition distributor; 21 – sensor of a detonation 2; 22 – bolt; 23 – sensor of a detonation 1; 24 – spark plug

Fig. 6.9. An arrangement of sensors of a detonation on the block of cylinders: 1 – wire; 2 – sensor of a detonation 2; 3 – bolt; 4 – sensor of a detonation 1

Fig. 6.10. Ignition moment sensor arrangement: 1 – high-voltage wire of the 4th cylinder; 2 – electric socket; 3 – ignition moment sensor

In the KE-Motronic system ( fig. 6.8 .) BOSCH as well as in Digifant, management of ignition and injection is carried out by one general control unit 9. The distributor of ignition 20 with Hall's sensor same, as well as in FEI (VEZ). The control unit, however, has in addition own diagnostics, it means that the malfunctions arising in system of ignition and injection register in memory of the control unit which can be interviewed, and the deciphered malfunctions will be purposefully eliminated. The power block, in comparison with other systems of ignition, is located near the coil 14 of ignition and aims to regulate ignition coil current on control unit signals. The KE-Motronic system has two sensors of a detonation of 2, 4 (fig. 6.9) which define a detonation in each separate cylinder and automatically change for them the ignition moment. The additional inductive sensor 3 (fig. 6.10) of the moment of ignition covers a high-voltage wire of 1 fourth cylinder and gives to the control unit at the time of ignition an ignition signal which is necessary for the analysis of signals of sensors of a detonation.

The distributor of ignition is installed in the block of cylinders on SOHC engines, and on DOHC engines it is established on a back part of a head of the block of cylinders and is put in action by the camshaft by the managing director of final valves.

Possible malfunctions of the generator, their reason and ways of elimination