Overview

The ignition system is to ignite the air-fuel mixture in each cylinder at precisely specified point of time. In gasoline engines, this is achieved by an electric spark (electric discharge) generated between the electrodes of a spark plug.

Reliable operation of the ignition system in the entire range of the engine - a significant factor in the effective operation of the catalytic converter.

Ignition spark small cloud of fine fuel mixture just sufficient to initiate the ignition process.

Plug determines the length of the spark, which depends on the type and design of the ignition system, and the conditions under which ignition occurs.

For the spark voltage between the electrodes candles should increase sharply from zero to the voltage required for the formation of an arc. After the occurrence of the spark discharge voltage drops to the level required for the dissemination of sparks - fuel mixture ignites.

For energy used sparking ignition coil, working on the principle of auto-transformer and energy storage ignition. When applying current to the primary winding of the ignition coil current of energy into the energy of the magnetic field until the termination of the current supply. The magnetic field decreases sharply, putting in a secondary winding of the ignition coil high voltage coming through the wires to the two spark plugs.

Between the initial ignition point fuel mixture and its complete combustion takes about 2 msec. Therefore, a spark should occur earlier than the piston reaches the TDC, which provides the optimum combustion throughout the range of engine speed. Ignition timing is determined depending on the engine speed, load, the design features of the engine, fuel quality and working conditions at the moment (starting, idling, the value of the throttle opening and so on. N.).

The spark plug is used to transmit high voltage, generated in the ignition coil to the electrodes in the combustion chamber where this current produces a spark to ignite the mixture.

Distribution and ignition timing is controlled by an electronic control module (ECM). Standard data on coal ignition timing for the engine operating conditions pre-programmed in the memory of ECM.

Modes of operation of the engine (engine speed, warm-up mode, and so on. D.) Are determined by a variety of sensors (Fig. 2.126). On the basis of these sensor signals and the angle of ignition timing stored in the ECM, signals are applied to interrupt the current in the primary circuit of the ignition coil. In the secondary winding of the ignition coil current is induced high voltage coming through the wires to the two spark plugs.