The ignition control unit supplies voltage to the primary winding of the ignition coil. At the required moment, the control unit disconnects the voltage from the ignition coil, which leads to a drop in the magnetic field in the primary winding and induces high voltage in the secondary winding of the ignition coil. High voltage at a certain moment from the ignition coil through the ignition distributor and high-voltage wires is supplied to a certain spark plug. When high voltage is supplied to the spark plug, a spark is formed between the electrodes of the spark plug, which ignites the fuel-air mixture in the engine cylinder. The moment of ignition of the fuel-air mixture is determined by an electronic control device.
The ignition timing is determined and continuously adjusted by the electronic control unit (ECU) based on information about engine speed, crankshaft position and vacuum in the intake manifold, received from sensors installed on the engine. Information about the throttle position is also taken into account when determining the ignition timing (removed from the throttle position switch), the temperature of the air entering the engine and the temperature of the coolant.
Depending on the type of fuel used, the initial ignition timing can be changed using a changeover plug located in the engine compartment next to the ECU.
Original can be found on the website (MercedesMan.ru)