The electronic engine control unit is programmed in such a way as to provide the optimal ignition timing for various engine operating modes. Using information about engine operating conditions (speed, coolant temperature, etc), the microcomputer issues a command to supply a spark at exactly the right moment in the engine's operating cycle.
The electronic control unit of the engine carries out current control over the conditions of its operation, using the signals of the corresponding sensors. Based on these signals, the electronic control unit calculates the required ignition timing and sends a control signal to the switch. The high voltage is distributed to the spark plugs according to the engine's firing order and causes a spark discharge between the spark plug electrodes, which ignites the air-fuel mixture.
Complex (combined) ignition block (block contactless ignition system) includes; a switch, an ignition coil, a spark discharge distributor for the engine cylinders, as well as rotors and inductive coils of the crankshaft angle sensor and the camshaft angle sensor.
The switch periodically interrupts the primary current coming from the electronic engine control unit (IGT signal), and thereby creates a spark discharge on the spark plugs. In addition, in order to improve the reliability of the ignition system, at the time of sparking, information about this (IGF signal) goes to the electronic engine control unit. The ignition coil consists of a closed core, a primary winding that wraps around the core, and a secondary winding that wraps around the primary winding. This design allows you to create a high voltage that can cause a powerful spark discharge in the gap between the electrodes of the spark plug. The ignition distributor distributes the high voltage to the spark plugs of each cylinder in accordance with the engine's firing order.
The NE inductive coil with magneto-electric pulse generator allows to determine the angular position of the crankshaft, and the inductive coil G - the angular position of the camshaft, which is necessary for the correct determination of the ignition timing.
Note' on some 4A-FE engines (version with Lean bum system) The camshaft angle sensors use two inductive coils G1 and G2.