In order for spark plugs to create a spark discharge, high voltage must be applied to their electrodes. Depending on the ignition system, this discharge voltage is over 30,000 volts.
Spark Factory - Ignition Coil
The ignition coils consist of two windings: a primary winding with a small number of turns (approx. 100) of thick copper wire (approx. 0.6 mm²) and a secondary winding with several thousand turns of thin copper wire (approx. 0.1 mm²). Both windings are surrounded by laminated iron cores. The primary winding receives current from the battery (low voltage) from the control unit via the built-in high-voltage module. This creates an electromagnetic field that excites the secondary winding. When the control unit interrupts this electrical circuit, the electromagnetic field also disappears instantly within a fraction of a second. A voltage of up to 400 volts then arises in the secondary winding, which generates a high-voltage current surge (induction) of over 30,000 volts. Mondeo engines have electronic ignition systems with twin-spark ignition coils which, in four-cylinder engines, fire their ignition sparks in the operating sequence 1-3-4-2 or 1-4-2-5-3-6 in V6 engines.
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