The main function is as follows. The control unit supplies the supply voltage to the primary winding of the ignition coil. The supply voltage is periodically interrupted by the electronic control unit and this is manifested in the disappearance of the magnetic field, which induces an even greater voltage, called high voltage, in the secondary winding of the coil. This high voltage is supplied by the distributor through high-voltage wires to the spark plugs in the cylinders at a certain moment. The electrodes of the spark plug have a gap small enough for a spark to occur between them and the spark that jumps ignites the fuel-air mixture in the cylinder. The ignition timing is critical to the operation of the engine and is therefore regulated exclusively by the ECU.
The ECU determines and controls the ignition timing and, first of all, the angle of the closed state of the contacts, in accordance with information about the engine speed, the position of the crankshaft and the degree of vacuum in the intake manifold, received from sensors mounted on the engine. Other parameters that determine the ignition timing are the position of the throttle valve, the temperature of the incoming air and the temperature of the coolant. These parameters are also monitored by sensors located on the engine.
The main ignition timing can be changed in stages to suit the type of fuel used. This is achieved by means of the compensator socket located in the engine compartment, next to the ignition ECU - refer to paragraph 5 for more information.
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